COST 507 Thermophysical Properties of Light Metal Alloys

Gra zy na J a ro ma-We i Ia nd Rud iger Bra ndt Gunther Neuer DISCLAIMER

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COST 507 Thermophysical Properties of Light Metal Alloys

Final Report

Grazyna Jaroma-Wei la nd Rudiger Brandt Gunther Neuer

Under Contract of BMFT 03K075 ISSN 01 73-6698 ASTE

February 1994 IKE 5 - 238

Un iversita t Stu ttgart ABSTRACT The thermophysical properties of AI-,Mg- and Ti-based light m studied by reviewing the literature published so far, evaluatin and by empirical investigations. The properties to be covered in are: thermal conductivity, thermal diffusivity, specific heat capacity, thermal expansion and electrical resistivity. The data have been stored in the factual data base THERSYST together with the results of experimental measurements supplied from participants of the COST 507 - action (Group D). Altogether 1325 data-sets referring to 146 alloys have been stored. They have been uniformly represented and critically analyzed by means of the THERSYST program moduli. These numerical data cover a number of systems with variing and thermal treatment. Partly large discrepancies especi conductivity have been found for similar alloyflry often the in corresponding publications are not complete enough to identify whether such discrepancies can be explained by other material related characteristics, such as thermal pretreatment etc. or whether experimental reasons are responsible. Therefore additional measurements are necessary in order to enable reliable statements upon variation of thermophysical properties (especially thermal conductivity) with chemical composition and microstructure.

The aluminium based alloys are very good heat conductors with thermal conductivities in the range between 70 Wm-'K' and 170 Wm%'. At measurements of thermal conductivity under steady-state condition a high heat flux has to be duced in the sample. This fact causes many difficulties during measurementsxe problem experimental ainties has been studied in detail by investigation of AA-8090 (AI-2.5Li-1.1 a number of experimental improvements could be realized. The data has been tested by comparative measurements of the same material with different measuring techniques in several laboratories. A low disagreement of 6% at room temperature and 4.5% at 200°C has been found. 7 The thermophysical properties (~een~udi~i~~~~r~~~i~sivity,Specifie-Reat- -eapaeity] of monolithic alloy KS1275 (AISil2CuNi) and metal matrix composite @ n,b (KS1275 reinforced with A,O, short fibre) have been determined experimentalld Thermal conductivity data have been used to apply theoretical models to describe the thermal conductivity of two-phase composites as a function of geometry and volume content of the components. Foreword

This study of the "Thermophysical Properties of Light Metal Alloys" was sponsored as Project No. 03K075 by the Bundesministerium fijr Forschung und Technologie (BMFI). We wish to thank Kolbenschmidt AG (Neckarsulm, FRG) and Vereinigte Aluminium Werke (Bonn, FRG) for supplying the specimens to be studied.

We express our thanks to the partners of COST507 action for good cooperation. Especially the contributions by A-M. Zahra (CNRS Marseille, France), W. Lacom (ARC Seibersdorf, Austria) and F. Richter (Muhlheim, FRG) have been important. Also the participation of L. Binkele (EA Julich, FRG) at the comparative measurement programme was very helpful.

Finally we are grateful to Prof. P.G. Klemens (University of Connecticut, Storrs, USA) for fruitful discussions about the theoretical modeling of the thermal conductivity of alloys. Contents

1. Aim of the study

2. THERSYST data base

3. Storage of thermophysical properties of light metal alloys in THERSYST

3.1 Literature sources 3.2 Transfer of the data from the COST partners 3.3 Thermophysical property data

4. Experimental investigations

4.1 Measurement methods 4.2 Materials to be studied 4.3 Measurements of thermal conductivity of good heat conductors by steady-state method 4.4 Comparative measurements on A48090 alloy 4.5 Thermophysical properties of metal matrix composite (KS1275/AI2O3-fibre)

5. Theoretical analysis of the thermal conductivity of metal matrix composites.

5.1 Models for the effective thermal conductivity of two-phase materials 5.2 Comparison of calculated and measured thermal conductivity data

6. Conclusion

7. References

Appendix

A: List of evaluated literature

B: List of materials and properties stored in THERSYST 1 1. Aim of the study

The rapid increase in the application of light metal alloys in the aerospace, automobile and transport industry, as well as in energy technique caused a great interest in thermophysical properties of these materials. Many light-metal-basedcomponents are exposed sometimes to temperatures up to 400°C, resulting in the generation of stationary or transient temperature fields. The knowledge of thermal transport properties enables the calculation of these temperature distributions and therewith predictions of chemical reaction and thermo-mechanical stresses of thermally loaded components resulting in creep, destructure, etc. Therefore it was decided to study the thermophysical properties of AI-,Mg- and Ti-based alloys in frame of the programme COST-507.

Is is well known that the thermophysical properties and especially the thermal conductivity of solids not only depend on chemical composition but also on chemical and thermal pretreatment of the material resulting in a variation of the micro- or macrostructure. The first aim of the study therefore was to critically analyse the literature with respect to available data and to relations between thermophysical properties and material characterization.

The measurement of thermal conductivity of high conductive metals are very difficult and it was a second aim of the study to improve existing measurement equipment in order to achieve higher accuracies and reliabilities of measurements of such materials. The availability of a number of laboratories in the frame of COST507 could be advantageously used to compare different measurements techniques and to test the reliability of the results.

Metal matrix components, which have been developed to improve mechanical properties of light metals, should be investigated experimentally because nearly no literature is available upon such materials until now. The experimental programme has been planned in order to find correlations between the thermal conductivity of a composite and the data of its components. Finally all data - the literature data and the experimental results of all COST507 laboratories have been made available by means of the data base THERSYST. The properties to be covered were: thermal conducljvity, thermal diffusivity, specific heat capacity, thermal expansion and electrical resistivity. 2 2. THERSYST - data base There are three data bases which deal with thermophysical properties of solid materials. The comprehensive data base system at CINDAS (West Laffayette, USA) covers all thermophysical properties for many groups of specific materials, such as dielectric materials, composite materials, high temperature materials, aerospace structural materials, etc [l].But these data are only accecible for limited groups of users and any cooperation with foreign partners is not possible. The thermal conductivity data base in Japan [2] deals with certified reference materials, candidates for reference materials, and other well-characterized materials. Other thermophysical properties (specific heat capacity, electrical resistivity, thermal expansion, and emissivity) are registered as supplemental properties only. ALUSELECT data base [3] has been developed to offer so-called harmonized values for aluminium and aluminium alloys, which can be further improved by the European Aluminium Association as the EAA official data. Data from the open literature, from the handbooks and from sheets of manufactures have been collected in the data bank but only evaluated values are accesible.

THERSYST database has been developed as a combination of a factual database for thermophysical of properties solids and a modular program system to handle the database content. The advantage of such a system is that program components can be added or deleted in a relatively easy manner to permit an optimum configuration.

As thermophysid properties are depending on material parameters and experimental conditions (meta-data), the information of all factors of influence should be stored in the data-base and the original context between the intrinsic properties data and meta- data should be preserved. This problem has been solved in THERSYST using the class concept [4]. The physical information is converted into a standardized form given by the THERSYST scheme of category and it is stored in the form of data-sets. The scheme of category is separated into five classes: class 1, material designation, class 2, material characterization, class 3, experiment description, class 4, thermophysical property data and class 5, bibliography.

Classes 1 to 4 are hierarchically structured, the class bibliography is linked to the corresponding data-set by a document number (Fig. 1). The information belonging to the data-set is stored in the form of descriptors, which can be numerical, coded or in text form. In Tab. 1 some important material and experiment parameters are listed, which are used in THERSYST as descriptors. It is also indicated, which thermophysical property is depending on.

The THERSYST modular programs system enables: - data selection corresponding to the criteria defined by user, data manipulation, e.g. conversion of units, variable transformation, regression of data, calculation of a new property from stored data on other properties, and ~ ... . 1 i' 3 I representation of data in the from tables and graphs.

A detailed description of these moduli is given in [5] .

Characterization

Statistics

DIALOGUE

Fig.1: Elements of modular system THERSYST for storage, handling and representation of thermophysical property data 4 Tab. 1: List of influence for the thermophysical properties

THC CP ELC LEX RAD -OPT chemical composition + + + + + + . electrical resistivity + + + + + + physical state + + + + + + particular form of material + + + + (e.9. fibre, powder, etc.) structure - microstructure + + + + - crystal structure + + + + + - lattice parameter + + + + + + - anisotropy + + + + + - porosity + + + + + - lattice impurity + + + + + - grain size + + + + + - phases at grain boundary + + + + + - geometrical arrangement of + + + + + + phases surface characterization + - roughness + - layer composition, thickness + phase transitions + + + + + - sample preparation + + + + + + sample treatment: - mechanical + - chemical + - thermal + + + + + + - irridiation + + + + + + . measurement technique + + + + + ambient atmosphere + + + + (com posit ion, pressure, ..) - measuring temperature + + + + + + - measuring frequency + spectral range + + +

THC thermal conductivity, thermal diff usivity CP specific heat capacity, enthalpy ELR electrical resistivity LEX thermal expansion (linear, volumetric) RAD emittance, transmittance, reflectance, absorptance OPT absorption coefficient, refractive index, extinction coefficient 5 3. Storage of the thermophysical property data of light metal alloys In THERSYST

The thermophysical property data of light metal alloys are depending on chemical composition and microstructure of the material, which can be affected not only during manufacturing process but first of all by the thermal treatment of the material. In account of it in the original papers a variety of representations is used, e.g. thermal conductivity as function of annealing temperature for different chemical compositions by fixed measured temperature, or as function of time for different aging times and temperatures, etc. The data are represented in different physical units and they are presented in different forms: as pictures, tables or in the form of equations. This "non- uniform" set of a data had to be transformed into a set of uniform classes being the base of final representations of comparable data and containing all information which is relevant for the actual purpose.

3.1 Literature sources

To find the data published so far, a computer search in the literature data banks METADEX and PHYS was made. The following properties were covered: thermal conductivity and thermal diffusivity, specific heat capacity and enthalpy, electrical resistivity, linear thermal expansion.

The search was made for the following material groups: - light metal alloys: aluminium-based alloys (AI-Cu-XI AI-Li-XI AISi-XI AI-TI-X and AI-Zn-X) titanium-based alloys (Ti-AI-X), magnesium-based alloys (Mg-X) - composites with light metal alloy matrix (AI- or Mg-based alloy) reinforced with AI,O, or Sic fibres, -whiskers or -particles.

The list of papers found were distributed among the COST-partners during the meeting in Amsterdam (June 21th, 1990). They checked it and sent additional publications. The computer searching in the literature data bases has been made every year. Publications found as suitable for the input have been evaluated and the data have been entered in the data-base. The bibliographic information on evaluated publications is listed in Appendix A.

3.2 Transfer of the data from the COST Dartners

The new experimental data measured in the frame of COST 507 action by partners A4, D1 and F2 have been also stored in THERSYST. The sets of data, Le. measured values and information on material characterizationand experimental conditions, have been supplied by means of floppy discs. Because of complexity of the data base it is installed at the mainframe now. For transfer of the data measured by partners of Group D a special PC-input program has been developed which enables to enter these data into THERSYST automatically [SI. The list of materials and properties 6 measured within group D and stored in THERSYST is presented in Tab.2.

Tab. 2: List of materials and properties measured in the frame of COST 507 and stored in THERSYST

...... THC THD CP ENT ELR LEX lSUM AMAt aluminium 111-12 6 BOALCUOO aluminium-copper alloy --8--- 8 BOALSIOO aluminium-silicon alloy --3--- 3 BOALZNOO aluminium-zinc alloy - -12 - - - 12 COALCUO2 AA-2017 -13--- 4 COALCUO3 AA-2014, AA-14s -11--1 3 COALCUO4 AA-2024, Ah-24s -37--414 cOALCUl2 aluminium-copper-magnesium-sum(x) -16--- 7 COALCU16 aluminium-copper-silver-sum(x) 1---1- 2 COALCU25 RR 350, aluminium-copper-nickel-sum(x) 1 - - - 1 2 4 COALCU26 Hontal S I--- 12 4 COALLIOl aluminium-lithium-copper-sum(x) 111-12 6 COALLIOZ Ah-8090, LITAL A 20 2 1 - 2 2 27 COALMGOl AA-6061 123--2 8 COALMG03 AA-5052, aluminium-magneeium-mum(x) - - 3 - - - 3 COALMGO4 AA-5083 --2--- 2 COATAGO7 aldnium-magneeium-silicon-sum(x) --3--- 3 COALMGOS AA-5754 -38--415 COALMGl2 AA-6063 -11--- 2 COALMG13 AA-5251 --3--- 3 COALMGl4 AA-5086 --2--- 2 COALS106 AA-6082 - 4 8 - - 113 COALS107 aldnium-silicon-magnesium-sum(x) --1-12 4 3.2384.6 COALS109 aluminium-silicon-magnesium-sum(x) --3--- 3 COALS111 A356 -22-- 1 5 COALS113 AA-6060 -15--1 7 COALS114 KS 1275 31---- 4 COALS115 AA-6005A -11--- 2 COALTI02 titanium-aldnium-tin-zirconium-eum(x)- - 1 1 - - 2 COALTI09 Tfi16V4, 3.7165 2-332212 COALTI20 Tikrutan LT35, 3.7110 --11-- 2 COALTI21 Tikrutan LT33 -- 11-- 2 COALZNO2 AA-7075, AA-75s 414-4821 AlZnMgCU 1.5 F 53, PERUNAL-215 COALZN05 aluminium-zinc-magnesium-sum(x) --7--- 7 COALZN06 AA-7010 -36--211 COALZNO7 AA-7020 -26--- 8 COALZN13 Titanal -15--3 9 COTIVQOl titanium-vanadium-aluminium-sum(x) --11-- 2 VMALOALO aluminium/A1203,SiO2 composite --I--- 1 VMALOALl A1203/KS1275 composite 1682-- - 26 VMALOALZ A1203/AA-6061 composite 336-- 5 17 VMCQALO aluminium/carbon composite -- 1--1 2 VMSICALO aluminium/silicon carbide composite - - 1 - - - 1 VMSICAL5 SiC/A-356 composite -12--1 4 7 3.3 Thermophvsical Drowrtv data

The actual status of the collection on thermophysical properties of light metal alloys and metal matrix composites is presented in Tab.3. Altogether 1325 datasets on 146 different materials have been stored, whereby 375 data-sets fall to the share of thermal conductivity and thermal diffusivity, 604 of specific heat capacity and enthalpy, 147 of electrical resistivity, and 199 of linear thermal expansion.

With respect to the large number of different alloys, these data cover a small fraction of possible systems. The systematical analysis of the collected data, according to the influence of the chemical composition and the thermal treatment on measured property was possible in the case of the specific heat capacity only. For this property a lot of data exists and for the most part detailled material characterisation is available. So it was possible to make reliable statements on the correlation between the specific heat and material/experimentaI parameters r,8].In the case of the thermal conductivity the situation is more complicated as it was shown in [9] on the example of AI-Cu-Ni-Mg alloys with different amounts of alloying elements and different thermal treatments.

Tab.3: Status of the THERSYST data base for light metal alloys (number of data- sets)

I I I Properties THD CP ENT ELR LEX I AI-cu-x I 28 96 14 148 - 33 33 I AI-ti-x I 3 121 3 38 - 6 7 AI-Mg-X 16 28 10 105 1 15 23 AI-Si-X 19 22

AI-X( Fe,Mn,Ni,Ti,Zr) 20 27 - 23 Mg-AI-X 7 10 2 2 - 15 12 Ti-AI-X 25 49 23 31 6 27 21 Ti-X (Fe,Sn) 3 2 MMC's 10 19

THC thermal conductivity CP specific heat capacity THD thermal diffusivity ENT enthalpy LEX thermal expansion ELR electrical resistivity 8 The evaluation of the data was very difficult, because the chemical compositions of samples to be studied differ and the informations about thermal treatment were not detailled enough. Similar problems occur if the data on the same alloy are analysed, e.g. on AM024 the best known and the most widely used aircraft material. In THERSYST 11 data-sets have been found. They are presented in Fig. 2 and in Tab. 4 the chemical composition and the thermal treatment of the samples are listed. The alloy requires solution heat treatment to obtain optimum mechanical properties. According to the German standard the heat treatments of particular specimens were follows [lo]: - 0: annealed - T4: solution heat treated, quenched and naturally aged - T86: solution heat treated, quenched, cold worked and artifically aged - T351: solution heat treated, quenched and stressed-relieved by controlled strecking to a premanent set and then naturally aged.

However, the designation of each tempering process does not define the temperature and time, and the details of the practice may be varied as desired or convenient if the end result as expressed by specified mechanical properties is unchanged. In the case of thermal conductivity this information is necessary, if the influence of thermal treatment should be discussed. Generell it is seen that annealing at elevated temperatures causes the remarkable increase of thermal conductivity values (data- sets: E0006229 and E0006230 or E0004736 and E0004737). A more quantitative gathering requires detailled investigations on samples with the well defined conditions of heat treatment.

-.-.- E0006036 1

.. ' E0006240

--* E000624 1 __ e - E0006263 - -6-E0006229 -.E-E0006230

50 i I I I I I I I -200 -100 0 100 200 300 400 500 temperature C Fiq. 2: Thermal conductivity of AM024 (literature data) 9 Tab. 4: Chemical composition and thermal treatment of AM024 alloy...... Signification of Descriptors EKEY data-set number CCOM chemical composition CCOM amount of element TREAT thermal treatment TRTEM temperature of thermal treatment EXMET measurement method DONO document number

EKEY I CCOM I CCOMA I D I TREATT I TRTEM I EXMET I DONO ------I------I------I---I------I------I------I------E0004736 I A1 I 93.40 W% I B I UNTR 1 --- I I TPSAM002 I cu I 4.500 I1 I I I 1 Mg I 1.500 I1 I I I IMn I 0.6000 I1 I I I E0004737 I A1 I 93.40 W% I B I ANNE 1 --- I I TPSAMOOZ I cu I 4.500 I1 I I I 1 Mg I 1.500 I1 I I I IMn I 0.6000 11 I I I E0005033 I I I I T4 1 --- I I P0000008 E0005034 I I I I T86 I --- I I PO000008 E0005035 I I I IO I --- I I PO000008 E0005224 I I I1 I --- I CLFA I ROO00127 E0005240 I A1 I 93.40 W% I B I I --- I CLFC I ROO00129 I cu I 4.500 I1 I I I 1 Mg I 1.500 I1 I I I IMn I 0.6000 I1 I I I E0005241 I A1 I 93.40 W% I B I 1 --- I CLFC I ROO00129 I cu I 4.500 I1 I I I 1 Hg I 1.500 I1 I I I IHn I 0.6000 I1 I I I E0005263 I A1 I 92.87 W% I B I 1 --- I CLFA I ROO00133 I cu I 4.490 I1 I I I 1 Mg I 1.470 I1 I I I IMn I 0.6600 I1 I I I I Fe I 0.3400 I1 I I I I Si I 0.1300 I1 I I I I Cr I 0.1000E-011 I I I I I Ti I 0.2OOOE-011 I I I I I Zn I 0.1000E-011 I I I I E0006229 I I I I T351 1 --- I CLFA I 50002974 E0006230 I I I I T351 I --- I CLFA I 50002974 I I I IANNE I 300.1 I Units...... of descriptors TRTEM [CI Signification of Codes B balance UNTR untreated ANNE annealed CLFA longitudinal heat flow absolute method CLFC logitudinal heat flow comparative method 10 The review of theoretical papers on thermal conductivity shows, that alloys are the most difficult systems concerning the analysis of different mechanisms responsible for heat transport. It is very complicated to determine quantitatively the influence of all scattering processes on the thermal conductivity [l1,121 caused by the complex structure of an alloy.

Direct thermal conductivity measurements are difficult, expensive and time consuming and cannot be performed on every material of interest. While the electrical conductivity is readily determined therefore for engineering purposes the most practicable way is to calculate the thermal conductivity from electrical resistivity. The empirical formula proposed by Smith and Palmer gives good results for the great group of ironchromiumnickel alloys. However, the detailled analysis of the experimental data on aluminium- and titanium-based alloys shows that for aluminium alloys the Smith-Palmer equations seems to be satisfactory for temperature above 500 K but it should not be applied for titanium alloys [12].

In metallic materials the heat is transported by two types of carriers: electrons and phonons (lattice waves), so the thermal conductivity is composed of two components: an electronic and a lattice component. The electronic component is related to the electrical resistivity by the Lorenz ratio. The theoretical considerations on mechanisms of electron scattering (e.g. electron-electron or electron-phonon interaction, scattering by solute atoms, etc.) led to the conclusion that for ordinary and high temperatures the electronic component can be calculated using Wideman-Franz-Lorenz relation. Besides the direct measurements of electrical conductivity, it can be predicted with help of thermodynamic considerations. Calculations from the solubility limits of the components in the solid state provide the accurate results for binary alloys [13]. However, the application of this method for heterogenous multicomponents alloy gives differences of 20% between the theoretical model and the experimental data [14].

The lattice thermal conductivity is governed by various interaction processes: anharmonic interactions between lattice waves, scattering of lattice waves by crystal impedections and solute atoms, and the interactions between lattice waves and free electrons. The interaction rates can be estimated by perturbation theory and so the lattice component of thermal conductivity can be calculated. So it seems to be the most real way to provide the thermal conductivity from the elctrical resistivity (estimated from an experiment or from theoretical considerations) and from the theoretical analysis of the macroscopic processes of the heat transport in metallic materials. 11 4. Experimental investigations

4.1 Measurement methods

4.1.1 Thermal conductivitv

For thermal conductivity measurements a commercial apparatus (Model TCFCM-N20) from Holometrix Inc., Cambridge, USA is used. The unknown test sample is sandwiched between two identical reference samples of known thermal conductivity. The stack is placed between two heater elements, where the main heater is controlled at a higher temperature than the auxiliary heater (Fig. 3). The heat generated in the main heater flows through the composite stack and the auxiliary heater into the water cooled heat sink. The resultant axial temperature gradients in the samples can be measured with two thermocouples in each sample (T, - TJ.

From the measured temperature gradients in both reference samples and their known thermal conductivity the axial heat fluxes can be calculated. At thermal equilibrium the heat fluxes through top and bottom references should be identical, if a pure axial heat flow through the stack (no radial heat losses) can be assumed. In most cases a flux difference of less than 10% can be tolerated. Then the mean value of both is assumed as heat flux through the test sample and the thermal conductivity of the test sample can be computed from the equation:

where s, and s, are the distances between the thermocouples in the sample and the reference samples and I+ is the thermal conductivity of the reference samples.

To ensure an axial heat flow through the samples without radial heat losses, the stack is surrounded by a cylindrical guard heater. The top and bottom temperatures of the guard heater are controlled at the same set points (Tl and T6) as in the stack, thus an axial temperature gradient in the guard heater is similar to that in the sample stack. To avoid convection and radiation heat transfer, the space between the samples and the guard heater is filled with a powder of very low thermal conductivity.

The power generated in the main heater determines the temperature gradient in the sample stack, while the power of the auxiliary heater fixes the temperature level of the stack. Usually a temperature drop in the stack of about 40 to 100 K is used. with direct contact between auxiliary heater and heat sink the lowest sample temperature is about 50 K above the coolant temperature. However, the heating capacity of the auxiliary heater is sufficient only to get sample temperatures of about 300°C. For higher sample temperatures one or more insulation sheets must be inserted between heat sink and auxiliary heater. Therefore measurements from temperatures near the heat sink temperature up to high temperatures cannot be carried out in a single run. The maximum temperature is determined by the lifetime of the heater wires and the 12 thermocouples and is fixed to 1OOO"C.

In order to get a high measurement accuracy, radial heat flux in the samples must be minimized, Le. the linear temperature drop in the guard heater should be approached as good as possible also in the sample stack. This means hat the thermal conductivity of the reference samples should match the expected conductivity of the test sample as close as possible and the contact resistance between test and reference samples should be minimized, which supposes plane sample surfaces and eventually use of a heat sink compound. Reference samples of four different materials are available:

material range of thermal conductivity and temperature 1. Pyrex7740 1 W/m K (R.T.) to 2 W/m K (450°C) 2. Pyroceram 9606 4 W/m K (R.T.) to 3 W/m K (lOOO°C) 3. lnconel 718 12 W/m K (R.T.) to 27 W/m K (1000°C) 4. Electrol. iron 75 W/m K (R.T.) to 30 W/m K (78OOC)

The thermal conductivity of the tested materials should be therefore in the range from 0.2 to 100 W/m K.

Reference samples are available in diameters of both 25 and 50 mm. Sample and references must have the same diameter. For materials of medium or low thermal conductivity the great diameter should be used in order to reduce radial heat losses, whereas for high conducting materials samples of only 25 mm diameter should be preferred in order to get a more uniform contact resistance. The reference samples are 13 and 25 mm in height. This should be also the range for the test samples. Thermal conductivity must be measured in thermal equilibrium. After each change in set point temperature it takes from 0.5 to 4 hours until thermal equilibrium has been restored and final test data can be taken. Thermal equilibrium is considered to be reached if the six temperatures measured in the sample stack don't change more than 0.1 K within 5 minutes. Due to the long duration of measurements the apparatus is fully automated. Up to 8 set points can be chosen in advance.

Normally the measurements are canied out in air. Measurements in inert atmospheres and in vacuum are also possible. However, due to the absence of gas 'conduction the contact resistance between the samples increases when measuring in vacuum and therefore the precision -of measurements is reduced. Furthermore the lifetime of heating wires and thermocouples is reduced for measurements in vacuum at high temperatures.

Wm carefully prepared and instrumented samples and a good match of the thermal conductivities of test and reference samples an accuracy of 90 to 95% can be reached. 13

upper guard heater

lower guard heater

Y ‘Y TI- T6 : thermocouples

Fa. 3: Schematic of comparative thermal conductivity apparatus 14

4.1.2 Specific heat wacitv

The specific heat capacity is determined by a differential scanning calorimeter (DSC) using a "Perkin-Elmer-DSC-2" apparatus in the temperature range of 230-1000 K. This is a relative method whereby the electric power delivered during the heating of the sample at constant rate is compared with that obtained during the heating of a reference of known specific heat under the same operating conditions. Sapphire (aluminum oxide) is employed as reference substance..

Three scans are required for the determination of the specific heat: first for the empty pan, second for the reference substance and the third for the sample. The same temperature range is used for each scan, and the heating rate and sensitivity are kept constant. During the measurements care should be taken to ensure that the baseline of the apparatus is kept constant during all three scans. Therefore it is recommended to subdivide the total temperature range in subranges of about 150 to 250 K (depending on the heating rate) in order to reduce the measurement time and thus to minimize drifts in the characteristics of the apparatus. The strength of the output signal at a particular temperature is measured with reference to baselines obtained by linearly connecting the corresponding initial and the final isotherms of each scan. The specific heat of the sample c,,~at any given temperature is then computed as

where m is the mass, c, the specific heat and y the strength of the output signal. The mass of the pan itself is not required in the calculations, as long as the same pan may be used for all the scans. This helps to reduce measurements and computational errors.

The measurement inaccuracy is below 3%.

4.1.3 Thermal diffusivitv

Measurements of thermal diffusivity are performed at IKE in the temperature range 500 - 2200 K using a modulated heating beam technique. A disc-shaped sample of 8 mm in diameter and about 1 mm in thickness is heated in a vacuum chamber at its front face by the radiation from a Xenon arc lamp via two elliptical mirrors (Fig. 4). The intensity of the light beam is modulated mechanically according to a sine-wave function. The resulting temperature oscillations on the heated sample face propagate through the sample and cause also temperature oscillations on the nonheated rear face, but delayed in time by a time difference AT.

The temperature oscillations on both sample faces are recorded either by PbSe infrared detectors (spectral range 3 - 4.5 pm) for sample temperatures below 1200 K or by photomultipliers (spectral range 0.4 - 0.55 pm) for temperatures above 1100 K. The phase shift between front and rear face temperature oscillation, Le. their time 15 difference AT is measured with a digital counter and sent to an online operating computer (pVAX 2) in order to calculate the thermal diffusivity a, which is roughly proportional to the square of the sample thickness I and inverse proportional to the time difference At: l2 a=0.46 E (3)

However, at high temperatures the heat losses from the sample surfaces must be taken into account. Additional measurement of the phase shift between the heating beam modulation and the rear face temperature oscillations permit corrections for these heat losses according to the theory of Cowan [lq. Because of disturbances in the electric signals of the detectors (noise, etc.) phase shifts are measured over some 10 to 100 periods, depending on the modulation frequency and temperature level. Only their mean values are used for calculation of thermal diffusivity. Furthermore, the computer program allows corrections of sample thickness due to thermal expansion.

’ The sample temperature is determined by measuring its rear face temperature either with a pyrometer (wavelenght 0.65 prn) for temperatures above 700°C or at lower temperatures with the IR detector also used for recording the temperature fluctuations. From the measured ’black” temperature the true rear face temperature TR is calculated by correction with the spectral emittance E~ of the sample surface. Because the sample is heated only on its front face the conduction heat flux Qc through the sample causes a temperature drop AT=Qr,l/Afrom the front to the rear face. This heat flux is equal to to the radiation heat flux QR = E,o(T;-T,~) on the rear face, so the temperature drop AT can be estimated by AT = x~E,~1 [e-e] (4)

where I=sample thickness, &thermal conductivity, %=totalemittance of the rear face, a=Stephan-Boltzmann constant, T,=rear face temperature, T,,=surrounding wall temperature. From the rear face temperature and the temperature drop the mean sample temperature is calculated.

Measurement errors, for example due to a nonuniform sample heating, cause the thermal diffusivity results to depend systematically on the modulation frequency. Therefore, at each predetermined temperature of measurement the diffusivity is measured at several different modulation frequencies. If a systematic dependency on the modulation frequency occurs, the results are rejected and the measurement has to be repeated.

The inaccuracy of thermal diffusivity measurements is lower than 6%. A detailed description of the apparatus and the measurement technique is given in (161. 16

pyrometer inert gas JI mirror 1 I €J mirror 2 modulation xenon-arc-lamp unit I sample /

detector 1 a

I +to vacuum system ir channel 4 I Jln

terminal computer ’ FVAX 2- 0

Fiq. 4: Schematic of thermal diffusivity setup 17

4.2 Materials to be studied

For experimental investigations we have obtained the following materials: a) AA8090 - AIU2.5Cu alloy produced by Vereinigte Aluminium Werke (VAW), Bonn; b) AISil2CuMgNimetal matrix composite reinforced with A,O, short fibres pro- duced by Kolbenschmidt AG, Neckarsulm.

The chemical compositions of the alloys and their conditions are presented in Tab5 The monolithic alloys have been received in form of bars. The MMC's have been supplied in form of an original piston bottom for diesel engines.

The composite was produced by a high pressure infiltration of a preform made from AZO,short fibres (trade mark SafFil from ICI) with liquid alloy at pressures up to 100 MPa [lv. The fibre orientation was random planar, Le. the long axes of the fibres were oriented preferentially normal to the squeeze casting direction but randomly oriented within this plane. The specimens investigated had fibre volume fractions of O%, 12% and 20% with densities of 2.70, 2.76 and 2.81 9/cm3, respectively.

Tab. 5: Chemical composition in weight % of materials under investigation and their conditions.

AA8090 NAW : solutionized (30min/535"C), water quenched, 2% cold deformed, aged 8h/210°C

Si 0,021 Mg 0,61 Cr <0,002 Fe 0,040 Zn 0,010 Zr 0,11 cu 1,10 Ti 0,022 Li 2148 Mn <0,002

AISil2CuMaNi (Kolbenschmidt: KS1275):

Si 1030 Ni 0,83 Pb 0,0119 Fe 0,50 Zn 0,0758 P 0,0025 cu 0,90 Ti 0,0432 Sr 0,0305 Mn 0,1694 Sn 0,0137 Mg 0,87 Ca 0,0002 18 4.3 Preliminaw investiaations

High precision measurements of thermal conductivity of good heat conductors (for AA8090 -100 W/mK are expected) with the apparatus described above are compli- cated. In order to measure the temperature gradients in all 3 smaples of the stack with satisfying precision, a temperature drop of about 50 to 100 K in the sample stack should be produced, which in the case of good thermal conductors requires a high axial heat flow through the samples. Because of the high thermal resistance of the bottom heater (made of Inconel) this great heat flux produces such a great temperature drop to the heat sink, that a minimum temperature of about 100°C could be reached in the sample. Therefore, for the low temperature measurements this heater was replaced by a good conducting brass cylinder.

At steady-state conditions the measured heat fluxes through top and bottom refer- ences should be'identical. If they show discrepancies, there are three different reasons:

1. True differencies in axial heat fluxes due to radial heat losses in the stack. However, in the case of good conducting samples the radial heat losses will normally be very low compared to the great axial heat flow and therefore are not relevant. 2. Measurement errors due to a mismatch of one ore more thermocouples used for measuring the temperature gradients. 3. Differences in local axial heat flow due to nonuniform contact resistance at the interfaces between test and reference samples. The temperature gradient is measured with thermocouples only in the center of each sample. In the case of good conducting samples with high axial heat flow local differences in the contact resistance may produce a non-uniformity in the heat flow and will result in discrepancies between the measured heat fluxes in the references.

On account of points 2 and 3 the measurements on sample with smaller diameter should be more reliable for measurement of good thermal conductors.

All these experimental problems have been studied in detail by investigations on AA8090 alloy (Fig.5). The measurements have been done in two temperature ranges from 50 to 125 "C (with brass cylinder) and from 100 to 200°C (with lnconel heater). Electrolytic iron was used as reference material.

The first four curves are obtained on the sample with a diameter of 50mm. In run 1 a heat flux difference of AQ = 16 % was observed between the two reference sam- ples. After machining of the sample surfaces AQ decreased to 12 %, combined with a decrease in measured thermal conductivity of about 20 %!I (run 2). Reexamination showed that the surfaces of the sample were slightly convex. After lapping of the surfaces AQ decreased to about 7%, and the measured conductivity increased again by about 15 to 28 % (run 7). However, there was a discontinuity of about 5 % in thermal conductivity values at 125"C, when the brass cylinder was replaced by the lnconel heater. Lapping of both the brass cylinder and lnconel heater surfaces led to 19 further improvements (run 11): the discontinuity at 135°C diminished to less than 1 %, AQ decreased further to about 5 %, combined with lower conductivity values in the lower temperature range.

The effect of inhomogeneity of the contact resistance across the interface of the samples can be minimized by minimizing the overall contact resistance. Therefore the influence of different contact materials on the temperature drop AT at the contact surfaces has been studied. Three measurements were carried out under the same measurement conditions (mean sample temperature: 200"C, temperature gradient in the sample stack: 100 K). The results are listed below: I AT I AQ without contact material 5% with bronze net (0.1 mm) 15 % with heat sink compund 2%

While the use of a silicone based heat sink compound improves the heat transfer markedly, a thin net of a good conducting material (0,l mm wire diameter of bronze) increased the contact resistance. It seem that the net is not enough ductile to deform and to adapt to unevenesses at the interfaces. As it has been expected, with decreasing temperature drop AT also the differences AQ in the heat fluxes of the reference samples decreased.

As mentioned above, samples with smaller diameter should be more suitable for measurements of good thermal conductors. Therefore additional investigations have been carried out on a specimen with a diameter of 25mm.

Compared with the conductivity date of the last run of the 450 sample (D 50, run 11) the first run of this sample (D 25, run 1) showed similar results up to 150"C, but about 5 % higher values at 200°C. The heat flux difference AQ varied between 8 and 12 %. When replacing the brass cylinder by the bottom heater a discontinuity in conductivity data of about 3 % was observed at 100 - 125°C. In run 2 the heat sink compound was used, which resulted in a decrease of AQ to about 2-7 % and also a decrease in the discontinuity to about 1,5 to 2 % at 100 - 125 "C. The thermal conductivity increased by about 4 to 6 %. From these data it is concluded that this last run (D 25, run 2) yield the most reliable conductivity results on the AABOSO alloy.

All these preliminary investigationsshow the sensitivity of the described measurement method to experimental conditions when applied to good thermal conductors. As a result of these investigations it was decided to perform all further measurements on small smaples (20 to 25 mm in diameter) and to use a heat sink compound to improve the heat transfer between the interfaces of the smaples and the reference samples. 20 4.4 Thermal conductivitv of AA8090 allov

As the preliminary investigations on the AA8090 alloy exhibit a high s ns it ivitv f the comparative steady-state measurement methods to experimental condiions a comparative measurement programme with 4 other laboratories has been initiated. In order to test the reliability of the measurement results samples of the same batch of material have been used. The list of participants and the applied methods are presented in Tab. 6. As ist can be seen from Fig. 6, the measurement results of the individual laboratories are in good agreement The scatter is about 8 % at 50°C and decreases to about 5 % at 200°C. Because the material had been aged at a temperature of 210°C (see Tab. 5) it is stabile only-. up to 200"C, and comparisons above 200"~are not significant.

Tab.6: Participants of comparative measurements on AA-8090 alloy.

~ laboratory I sample dimen- I method sions Mannesmann calculated from electrical rod, 08x135 Forschungsinstitut (Dl) resistivity using Palmer- Duisburg Smith relation KFA Julich') modified Kohlrausch meth- rod, 05x130 I Od ARC Seibersdorf (A4) comparative steady-state method, reference sample: IKE Stuttgart (05) electrolytic iron disc, 050x28 025x28

') Forschungszentrum Julich, KFA, Dr. L. Binkele -. __ - _.-.. . - - ......

21

'f 60 80 100 120 140 160 180 200 temperature C

Fia.5: Thermal conductivity of AA-8090 alloy measured at IKE on samples with diameter of 50mm and 25mm. 22

,A , - ,, , +3- Mfl, heating ,, -0-Mfl, cooling ,,, I --&- ARC - R - IKE, D25, run 2 - -*-KFA, run 1 -4- KFA, run 2

-

-

-

80' I I I I I I

temperature C

Fia.6: Comparative measurements on AA8090 alloy 23 4.5 Thermophysical properties of metal matrix composites

4.5.1 Specific heat capacity

The specific heat capacity was measured by differential scanning calorimetry (DSC) using a Perkin-Elmer-DSC-2,

The matrix material AISil2CuMgNi itself and the composites reinforced with 12 and 20 % Al,O, fibres were investigated. All measurements were carried out under argon atmosphere in the temperature range from 80 to 500°C with a heating rate of 20 K/min.

In a first measurement series these three materials were measured by a "standard" procedure, i.e. the specific heat capacity was estimated successively during heating in two temperature subranges (see chap. 4.1.2). The results, especially for the matrix sample, showed a markedly increase in specific heat data above 300°C which was attributed to an instability in the material structure. If such a change in structure causes an endothermic reaction it will falsify the specific heat data to be too high, i.e. correct measurement of specific heat capacity will not be possible by dynamic methods in those temperature ranges where structural changes occur. However, these effects can be diminished by heating successively in only small temperature subranges with intermediate pauses at constant temperatures to allow the reactions to fade away.

Tab.7: Specific heat capacity c, of Al12SiCuMgNi matrix and the composite rein- forced with 20% AI,O, short fibres

T ("C) cp (J g-' K-') AlSi 12CuMgNi 20 vol% AI,O, 60 0.863 0.858 100 0.906 0.903 150 0.929 0.936 200 0.949 0.962 250 0.968 0.983 300 0.982 1.005 ' 350 1.004 1.029 400 1.035 1.056 450 1.078 1.110 500 1.137 1.194 24

p”

0.8 I I I I I I I I I I 0‘ l00 150 50 200 250 300 350 400 450 600 temperature C

Fia.7: Specific heat capacity of composite KS 1275/AI,O,

Therefore, in a second series the whole temperature range was subdivided into 9 subranges, 3 subranges from 80 to 320”C, where no reactions had been observed, and 6 subranges from 300 to 500°C. After each scan in one subrange the tempera- ture was kept constant for 5 minutes before starting the scan in the next higher subrange. Above 300°C only the specific heat capacity value obtained at the begining of the scan was taken as result. Additionally measurements were carried out also during cooling from the maximum temperature with a cooling rate of 20 K/min and using the same temperature subranges than during heating. Because this procedure was very time consuming and, on the other hand, the first measurement series indicated that the specific heat capacity is very similar (difference less than about 3%), only the matrix material and the composite with 20% fibres was measured. The specific heat capacity of the composite with 12% fibres can be estimated with sufficient accuracy by interpolation.

The results are presented in Tab.7 and Fig.7. Because the results obtained during heating and cooling differed not more than about 0.5% only their mean values are given in Tab.7. The specific heat capacity of the composite with 20% fibres is the same as that of the matrix at 80°C and is only about 2,3% higher at 500°C.

Comparison with the results obtained from the first measurement series show that above 300°C the continous heating produces errors in specific heat data due to endothermic reactions which at the maximum temperature of 500°C yield too high specific heat values of about 15% in the case of the pure matrix material and about 5% for the composite with 20% fibres. 25 4.5.2. Thermal conductivitv

The thermal conductivity of the AZO3short fibre-reinforced AISil2CuMgNi was investigated for the two fibre concentrations of 12% and 20% as well as for the pure matrix material. In order to study the anisotropy effect thermal conductivity was measured parallel and perpendicular to the fibre planes (see chap. 4.2). The reinforced specimens were cut from two piston bottoms with different fibre concentra- tions. Because these piston bottom were only about 21 mm thick, only small samples of 20 mm in diameter and 20 mm in height could be manufactured. The reference samples (electrlytic iron) were also machined to a diameter of 20 mm. The thermal conductivity results of all 5 smaples are presented in Fig. 8. The numerical values are listed in Tab. 8.

Aluminium-based materials are very sensitive to thermal treatment. For all five samples the thermal conductivity values measured during the cooling run are higher than during heating. At the pure matrix material an increase of more than 7% was observed at 150"C, at the composite materials the increase was only of about 1% to 2%.

The reinforcement with A,03 fibres leads to a significant reduction of the thermal conductivity in comparison to the monolithic alloy. During the first heating run that reduction depends on temperature, e.g. in the case of the sample with 12vol% AZO3 and the heat flow parallel to the fibre plane the thermal conductivity was lower about 13% at 50°C and even about 24% at 500°C than that of the matrix alloy. However, during subsequent cooling the reduction was found to keep constant with temperature. Compared to the matrix material the thermal conductivity of samples with 12~01%fibres was lower about 23% at heat flow parallel and about 28% at heat flow perpendicular to the fibre plane, for samples with 20~01%fibres the thermal conductivity is lower about 32% and 43%, respectively. The mean anisotropy ratio of the 12~01%specimen is 0.92 and that of the 20~01%specimen is 0.8. 26 Tab. 8: Thermal conductivity h of the unreinforced matrix AISil 2CuMgNi and AI,O, short fibre reinforced aliminium alloy for different concentration of reinforcement and for different heat flow directions: parallel (I) and per- pendicular (I)to the fibre plane.

1

I ~~ 12 Vol% fibres AISil2CuMgNi I I I I 50 146.0 126.5 115.6 108.9 89.3 100 147.4 125.0 115.2 108.6 88.5 150 148.5 123.3 113.3 107.6 - 200 150.0 122.0 112.5 106.2 88.1 300 151.6 121.2 112.5 105.8 08.5 400 149.0 117.0 108.3 100.4 - 500 147.0 111.6 103.0 97.8 83.5 400 155.2 119.2 110.0 103.7 87.1 300 159.1 123.5 114.7 108.0 89.7 200 159.8 123.7 116.7 108.3 90.0 150 159.4 124.7 117.5 108.5 92.8

As reported earlier the thermal conductivity of KS1275+20% AI,O, has been also determined at ARC, Seibersdorf (A4) and at KFA Julich (methods see Tab.6) [18]. Parallel to the fibre planes KFA obtained data about 30% higher than the IKE results, but generally show the same slightly negative slope versus temperature (see Fig. 9). Perpendicular to the fibre planes KFA could measure only at 40°C. This value is about 10% higher compared to IKE results (see Fig. 10). The values measured at KFA by the modified Kohlrausch method hat to be corrected by a factor taking into account the nonconducting phase of A1,0, fibres. This factor was calculated from the simple model for reinforced alloy, in which all fibres are placed parallel to the heat flow. This model seems not to be appropriate for the investigated material and may be a source of error. At ARC thermal conductivity was measured only perpendicular to the fibre planes. At low temperatures the results are similar to the IKE data, but the ARC data generally show a positive temperature slope, so at the maximum temperature (400°C) their values are about 26% higher than the IKE data. The reasons for these discrepancies are not yet clear and demand for further investigations. 27

I 1- I I I 160 -

150 - ,. --st AlSi 12CuMgNi -8- 12% paralel - 140 --&- 12% perpend Y -8- 20% paralel E -e-20% perpend 2 130 -

120 3c 0 -0 Dl&E 110- c,

100 -

4. 90 -

I I I I I 8oA 100 200 300 400 500 temperature C

Fia.8: Thermal conductivity of KS1275/Al20, composite measured at IKE 20

1501 I I I I I I I I I

140

Y $130

I I I I 1 I I I I

temperatwe C

Fia 9: Thermal conductivity of MMC KS1275/20%A120 parallel to the fibre plane

-+ KE 120 - -.*.-

I I I I I I I I I 50 100 150 200 250 300 350 400 450 so0 temperatwe C

Fia. 10: Thermal conductivity of MMC KS1275/20%A120, perpendicular to the fibre plane 29 4.5.3 Thermal diffusivity

Thermal diffusivity was measured also on 5 different smaples as for the conductivity measurements: composites with fibre concentrations of 12 and 20%, two samples cut of each concentration parallel and perpendicular to the fibre planes, and the matrix material itself. The measurements were carried out in the temperature range from 200°C to 500°C in heating and subsequent cooling cycles. Due to the short measure- ment time it was possible to observe the time-depending changes of the material. At a constant temperature of 500°C the thermal diffusivity of the monolithic AISil2CuMgNi increased by about 15% within 40 minutes, that of the composites only by about 7% for both measured directions (Fig. 11). The numerical values are presented in Tab.8.

Tab. 9: Thermal diffusivity a of the unreinforced matrix AISil2CuMgNi and A120, short fibre reinforced aluminium alloy for different concentration of rein- forcement and for different heat flow directions: parallel (I) and perpen- dicular (I)to the fibre plane.

a Icm2 s-' 1 Matrix 12 vol% fibres 20 vol% fibres AlSi 12CuMgNi I I I I 300 --- 0.343 0.31 4 ------350 0.407 0.324 0.310 0.269 0.260 400 0.388 0.322 0.301 0.256 0.247 450 0.346 0.301 0.300 0.255 0.243 500 0.367 0.31 3 0.301 0.262 0.236

500 0.41 3 0.339 0.322 0.285 0.253 450 0.442 0.370 0.344 0.308 0.269 400 0.480 0.385 0.362 0.31 8 0.276 350 0.51 6 0.405 0.377 0.334 0.277 300 0.592 0.421 0.399 0.355 0.290 250 0.647 0.454 0.428 0.382 0.325 200 -- 0.481 0.439 0.392 0.336 * Al12SiN -A- 12%paralel -4- 12%perpend -e - 20% paralel

-%a- 20% perpend 0.55 \ ,zv) 0.5 c

0.25 1 0.21 I I I I I I 200 250 300 350 400 450 500 temperature C

Fia. 11 : Thermal diffusivity of KS1275/Al20, composite. 31

5. Theoretical analysis of the thermal conductivity of metal matrix composites

5.1 Models for the effective thermal conductivitv of two-phase materials

The problem of determining the effective transport properties of multiphase materials dates back to Maxwell [19], who considered a spherical inclusion within a matrix cube as a function of relative volumes. Since this time a number of analytical models have been proposed to predict the effective thermal conductivity of composites. The list of literature dealing with this problem can be found e.g. in [20-221. Many of these models are oriented towards continous fibre or particulate composites. For short fibres composite models developed by Hatta and Taya [21], by Hasselman and Johnson [22], and by Klemens [23, 241 can be used.

The model proposed by Hasselman is based on the original theory of Maxwell, which permittes the derivation of two phase materials consisting of a continuous matrix phase with dilute concentration of dispersion. The Maxwell theory has been modified regarding a thermal barrier resistance at the interface between the components. Such barriers arises from the combination of poor mechanical or chemical adherence at the interface and a mismatch in the coefficient of the thermal expansion. This thermal resistance is characterized by an interfacial heat transfer coefficient h, defined as heat flux through boundary q,and the temperature gradient accross it AT;

qi = hAT, (5)

- A2 A A2 A2 - (- - 1 - 2)f+ (1 + - + -1 XI ah ah A,

Hatta and Taya [21] have developed a theory based on an equivalent inclusion method, proposed by Eshelby for elasticity. This theory takes into account the inter- action between various fibres and therefore is valid also for higher values of a rein- forcement. For twodimensional orientation of the fibres in the matrix as studied here, and for heat flow in the fibre planes they have obtained the relation:

f (A2-A,) (1, - A,) a + 2A,I A, = 1, 1 + (7 1 { a1u2- a,) (2-f)a + 2a: 1 A new approach to the problem of the effective thermal conductivity of inhomoge- 32 neous media has been proposed by Klemens [23,241. There the effective thermal conductivity he is defined in terms of the rate of entropy production per unit volume in unit temperature gradient. The local thermal conductivity is expressed as a Fourier expansion about its volume average h, and higher order terms of the expansion are neglected. For composites reinforced with randomly oriented fibres in parallel planes the thermal conductivity is anisotropic. For this case he becomes: he = h, - [(I - sin2a) / 4h,] f (1 - f (hL,-h2)z (8) where a is the angle between the temperature gradient and the fibre plane. The effective thermal conductivity has a minimum in the direction normal to that plane (sin a=1) and a maximum in the direction lying in that plane.

5.2 Comparison of calculated and measured thermal conductivitv data

Comparison of the experimental observations with the predictions of the above mentioned models at 100°C is presented in Tab.10. Thermal conductivity of N203 fibres was estimated by the producer of the composite to be 5 Wm-'K-' (251. In the case of the heat flow parallel to the fibre plane the prediction of the Klemens (eq.8) and of Hatta and Taya model (eq.7') agree within 3% with measured values. For the heat flow perpendicular to that plane differences of 5% and 18% between measured and calculated values are observed for specimen with 12~01%and 20~01%inclusions, respectively. For the Hasselman model (eq.6) the coefficient h is necessary, which was not determined yet. The measured and calculated data are consistent with an h value of 1.1 O4 Wrn-,K-' . It is a relatively small value for the heat exchange and it represents a behaviour rather closed to an insulating interface (h = 0) than to a perfect interface (h = 00).

Tab. 10: Observed and predicted thermal conductivity h wm-'K-'] of alumina rein- forced A112SiCuMgNi at T = 100°C parallel (I)and perpendicular (I)to the fibre plane

On the other side from analytical transmission electron microscopy on aluminium- based MMCs reinforced with Al,O,-fibres [26, 277 and particles [28] it is known that alumina reacts with the matrix material forming spinel (MgAl,O,) at the interfaces 33 which causes a good chemical bonding between matrix and reinforcement. In the case of the fibre reinforcement that layer can be larger than lpm whereas the fibre diameter of the investigated composites is only 3pm. For such materials the theory for effective thermal conductivity of composites with coated dispersion developed by Hatta and Taya [29] could supply a better approximation of experimental results. However, this model supposes the knowledge of the thickness and the thermal conductivity of these layers.

The investigated MMCs have a great difference in the thermal conductivities of their components. For the volume fraction of inclusions discussed here the effective thermal conductivity depends primarily on the conductivity of the high-conducting phase, i.e. the matrix. The thermal conductivity of aluminium-based materials depends on their metallurgical state and there is no guarantee that a matrix in MMC is in the same conditions as the monolithic alloy, even if both materials have the same thermal history. We have observed (Fig.8) that the increase in the thermal conductivity of the monolithic alloy after the heating run was greater than that of the composites. Also the thermal diffusivity measurements show that at a constant temperature of 500°C the thermal diffusivity of the monolithic AISil2CuMgNi increases by about 15% within 40 minutes, that of the composites by about 7% only (Fig.11). Because of the good thermal stability of the fibres the increase observed in composites can be caused by variations in the matrix or/and in interfaces only. The aluminium solid solution in AISil2CuMgNi is hardened by Mg,Si precipitates. In the above mentioned structural investigations [26] precipitate free zones around the fibres were observed and while magnesium was bonded to the fibre matrix interface, both solid solution hardening and precipitation hardening were diminished. Also the microscopic observations and the measurements of electrical resistivity of AA6061/Saffil-fibre composite show that the level of precipitation hardening decreased significantly with increasing fibre volume fraction [30]. 34 6. Conclusion

6.1 Literature Review

A large number of experimental results on thermophysical properties of light metal alloys is available in the literature. However, the practical value with respect to the application of the data at thermotechnical calculations, such as temperature fields in components, is limited because of the following problems:

- Systematical analysis of the data on thermophysical properties is very difficult because they may be affected highly by variations in chemical composition and thermal treatment. Very often the material characterization is either not available or is not detailled enough, so these data can not be compared with others. In cases where experimental results are published of materials differing in both chemical composition and thermal treatment, it is impossible to find a correlation between the thermopyhsical data and the material parameters. - From the theoretical point of view, alloys belong to the most difficult systems, concerning analysis of different mechanisms responsible for the heat transport. Therefore it is complicated to predict thermal conductivity from theoretical con- siderations. However, it is possible to formulate a relation allowing with some confidence to determine thermal conductivity from electrical resistivity measure- ments.

6.2 Experimental Investiaations - Precise measurements of the thermal conductivity of alumunium alloys may be very complicated. They are very sensitive to the experimental boundary conditions (preparation of a specimen, measuring procedure, etc.), caused by the high thermal conductivity and the structural instability of the material with a changing temper- ature. Detailled investigations and comparative measurements with other COST- 507 partners led to essential experimental improvements with respect to the accuracy and reliability of the results. Reasons for remaining descrepancies between the results of different laboratories could be given and it might be ex- pected that new comparative measurements , planned for the next round will completely agree.

- Extensive investigations of the thermal conductivity of MMC’s have been performed in order to compare experimental results with data predicted from theoretical models. The used models are related to two-phase materials with perfect thermal contact between individual components (Klemens or Hatta & Taya models). Consideration of the existence of the thermal barriers between matrix and reinforcement (Hasselman model) gave better agreement between measured and predicted values. But no model takes into account the complicated microstructure in MMC’s. Generally, it can be stated that available models lead to values which are higher than the measurement results. Further investigations will be necessary in order to improve the theoretical models and to predict the thermal conductivity of 35 an MMC, e.g. if the volume content or the type of fibre shall be changed.

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List of evaluated literature A1

AX000025 Richter P. 'Die physikanlischen Eigenschaften der beiden Titan-Werkstoffe Ti99.7 (3.7035) und TW6V4 (3.7165)' Uetall 42(1988),572-575 AX000027 Richter P.,Born L. 'Die mpezifimche Waermkapazitaet von ntallimchen Werkstoffen. Tail 111.' l.Werkstoffterch. 17(1986),233-237 50 0 000 23 Gupta X.P.,Cheng C.B.,Beck PA. 'Low-temperature specific heat of Hi-base fcc molid solutions with Cu, an, Al, Si and Sb" Phym.Rev. 133(1964),AZ03-A206 50000057 lrudmky D.R.,Delinger W.G.,Bavage W.R. 'specific beats ff alpha-phame Cu-Al and dilute vgnetic Cu-Al(Pe) alloys Phys.Rev. B3(1971),3025-3032 50000064 Shinozaki S.S.,Arrott A. 'Electronic specific heat of dilute aIloys:Pe(Ti),Pe(V), Pe(Cr),Pe(Un),Pe(Co) Pe(Ni),Pe(Al),Pe(llo),Pe(W) and Ag(Au)' Phys.Rev. 152(1966),611-622 50000077 Kitchell U.A.,Klemens P.G.,Renolds C.A. 'Lattice thermal conductivity of plastically deformed copper plus 10 atomic percent aldnum specimens in the temperature range 1-4K' Phy8.Rev.B 3(1971),1119-1130 50000084 Uacchioni C.,Rayne J.A.,Bauer C.L. 'Low-temperature resistivity of bulk copper-aluminum alloys' Phy8.Rev.B 25(1982),3865-3870 50000095 pventouri,Cavin O.B.,Paulkner 5.8. Preliminary study of the thermal-expansion coefficients of long-range-ordered aluminides" Phys.Rev.B 31(1985),7436-7439 50000229 Chevrier J.,Pavuna D.,Pourcaudot G. "On elfctronic properties of rapidly quenched Al-Si alloys Solid State Comm. 55(1985),431-433 50000238 Sawides N.,Aurd C.U.,UcAlimter 6.P. "Electrical resistivity of some niobium A15 compund" Solid State Comm. 41(1982),735-738 50000245 Powell R.W.,Tye R.P. "The thermal an! electrical conductivities of two further titanium alloys J.Lemm-Coamom net. 5(1963),297-299 JO 000 332 phizanovskii R.E. The themphysical properties of titanium and the thermal conductivity of its alloys with tin and aldnum' Bigh-Temp. 2(1964),359-362 50000477 XaretSkii E.B.,Peletskii V.E. 'Them-physical properties of solid solution of the ternary mymtem Ti-Al-V' Teplofiz.Vys.Temp. 18(1980),990-994 500 00483 XaretSkii E.B.,PeletSkii V.E. 'Them-physical properties of Ti-Al system solid aolutions in the temperature range 750-1700 fa Teplofiz.Vys.Temp. 18(1980),84-91 50000508 Peletskii V.E.,Xudryavtsev A.S.,Amasovich Ye.S., et all 'Temperature variations of some physical properties of new titanium alloy PT-3V (4.7%Al,2.248V)' 1zv.Akad.Nauk SSSR,Met. (5)(1981),120-122 50000878 McXay J.A.,Schriempf J.T. "Corrections for nonuniform surface-heating errors in flash-method thermal diffusivity measurements' J-Appl-PhyS. 47(1976),1668-1671 J0001033 Belyaev R.A., Biryukov I.H., Barinov V.V. 'Linear expension of high-alloy steels urd alloys" Teplofiz.Vys.Temp. 17(1979),748-753 J0001179 Iliyev L.B., Ovchrrenko V.I., Pervakov V.A. .Low Temperature Beat Capacity of Commercial.Grade Titanium VTl-0 and its AllOyS VT5 and VT5-1. Pys..Het.Hetall. 46(1979),34-39 J0001183 Xlobintsev G.H.,Iliyev L.B.,Kozinets V.V.,et a1 'Low temperature heat conductiyity of solid Solutions of aluminium and tin in titanium. Phys.Het.Hetal1. 47(1979),167-169 J0001673 Hartin J.P.,Dode D.B. "Low-teerature molar heat capacities and inter-relations of thermodynamic properties of (copper + aluminium) alloys' J.Cher.ThemodpamicS 12(1980),787-796 J0001786 Fezdrliyan A.,HcClure S.L.,Taylor R. Theraophysical measurements on 90Ti-6Al-4V alloy above 150 K using a transient (subsecond) technique" J.Res.Nat.Bur.Stand. 81A(1977),251-256 JOOO 1831 Narkworth l4. "Anisotropie elektrischer Leitfaehigkeit bei warmausgehaerteten AlXnNgCu Lagierungen.' Hetall 32(1978),579-580 JOOO1900 Bust J.G.,Weitzel D.H.,Powell R.L. "Thermal conductivity,electrical resistivity and thempower of aerospace alloys from 4 to 300 K' J.Res.Nat.Bur.Stand 75A(1971),269-277 50002732 Xlobintsev G.H., Xozinec V.V., Xerisov B.A., et al. 'Thermal conductivity of titanium alloys at low temperature" Xhim.Neft.Hashinostr. 11(1978),12-13 J0002806 Powell R.W.,Hickman K.J.,Tye R.P. 'The thermal and electrical conductivity of magnesium and some magnesium alloys." Hetallurgia 70(1964),159-163 J00028 11 Erwlaev B.I. "Thermal conductivity and electrical conductivity of materials based on titanium and its alloy at temperatures from 20-80 to 1OOOK. Hetal Sci.CHeat Treat. 16(1974),1049-1051 JOO 0 282 8 Neimark B.E., Korytina S.P., Nonina L.P. et al. 'Experimental study of the physical properties of alloys with a base of VT-5 titanium and VT-8 titanium." Heat Transf.-Sov.Res. 5(1973),4-6 JO 00 2 8 34 Czochralski J. 'Silumin, eine neue Leichtlegierung" I.Hetallk. 13(1921),507-510 50002836 llannchen W. 'Waermeleitvermoegen, elektrimches Leitverroegen und Lorenzsche Zahl tiniger Leichtmetall-Lcgiarungen." X.Hetallk. 23(1931),193-196 J000286 1 Bungardt W.,Kallenbach R. 'Weber die thermische und elektrische Leitfaehigkeit von Aluminium und einigen Aluminiurlegierungen bei Tezperaturen bis eu 400c." X.Hetallk. 42(1951),82-91 J00028 62 Donalddson J.W. 'Thermal conductivities of industrial non-ferrous alloys" J.Inst.Hetals 34(1925),43-56 500028 63 !riffithe E.,Schofield P.H. The thermal and electrical ynductivity of some aluminium alloys and bronzes. J.Inst.Hetals 39(1928),337-374 A3

50002868 Bode X.H.,Pritz W. 'Eine neue Apearatur zur Uessung der Waeraeleitfaehigkeit von Uetallen. l.Angew.Phys. 10(1958),470-479 J0002879 Shelton S.U.,Bvsnger W.H. "Thermal conductivity of irons md steels and some other metals in the temperature range 0 to 600C.' Trans.Am.Soc.Stee1 Treating 21(1933),1061-1078 50002886 Griffiths E. 'The thermal and eleerical conductivity of a single crystal of aluminium. Proc.Roy.Soc.(Iandon) A115(1927),236-241 JOOO2899 Smith C.S.,Palmer E.W. 'Thermal and electrical conductivities of copper alloys' Trans.AIUE 117(1935),225-243 J0002906 hybrey E.J. 'Thermal conductvities of some light alloys' Uetal Ind.(London) 33(1928),5-6 J0002912 Bidwell C.C,Eogan C.L. 'Therma! conductivity of aluminum; solid and liquid states. J.Appl.PhyS. 18(1947),776-779 50002930 Wagner R.X.,Xline H.E. 'High strength zirconium alloys' Trans.Am.Soc.Hetals 52(1969),713-727 J0002932 pcken A.,Warrentrup H. Die Veraenderlichkeit des thermischen und elektrischen Widerstandes bei der Ausscheidungshaertung von N-Cu-Legierungen.' l.Elektrochem. 41(1935),331-337 50002944 Biran de A. 'Lea proprietes thedquea de l'aldnium et leurs applications.' Rev.NUninium 11(1934),2311-2330 J0002946 Rhodes B.L.,Uoeller C.E.,Sauer H.J. 'An apparatus for deteremining thermal conductivity of solids from 20 to 600 1.' Cryogenics 5(1965),17-20 50002947 Xiegler W.T.,Uullins J.C.,BWa S.C.P. "Specific heat and thermal conductivity of four commercial titanium alloys from 20 to 300X. Mvan.Cryog.Eng. 8(1963),268-277 50002968 Boehm R.,Wachtel E. 'Aufbau einer Uessanordnung zur Besthung der Transport-Xoeffiezienten von Uetallen und Legierungtn in Abhaengigkeit von Temperatur mch dem Kohlrauech... X.Uetallk. 60(1969),505-514 50002972 William R.X.,Graves R.S.,Weaver F.J.,Yarbrough D.W. 'Effect of point defect 09 the phonon them1 conductivity of bcc iron. J.Appl.Phys. 62(1987),2778-2783 50002973 Logunov A.V.,Xverev A.P. "Investigating the thermal conductivity and electrical resistance of aluminum and of a qroup of aluminum alloys.' J.Engng.Phys. 15(1968),1256-1260 50002974 Farda X.,&ck J.V. "Numerical molution of transient heat conduction equation for heat-treatable alloys whose ttermal properties change vith the and temperature. J.Heat Transfer 99(1977),471-478 50002977 larichnyak Yu.P.,Lisnenko T.A. 'Theraophysical properties of Al-Ug-ln solid solutions' Izv.WG,Priborostr. 20(1977),116-119 J0002983 Xlobintsev G.U.,Xozinets V.V.,Nerisov B.A.,Ogneva E.U., Sokolov V.I.,Blinova A.V. 'Thermal conductivity of structural aluminum alloys at low temperatures.' Uet.Sci. L Heat Treat. 17(1975),136-437 A4

50002986 Jorstad J.L. 'The hypereutectic aluminum-silicon alloy used to cast the Vega engine block' Hod.Cast 60(1971),59-64 50002987 Chewier J.,Pavuna D.,Cyrot-L.ckm&nn P. 'Electronic properties'and (meta)stability of rapid quenched A1-Si alloys. X.Phys.Chem.Neue Polge 157(1988),289-293 J0003005 Brandt R.,Pawlovski L.,lOeuer G.,Pauchafs P. "Specific heat and thermal conductivity of plasma sprayed yttria-stabilized zirconia and nickel-aluminum, nickel-chromium, nickel-chromium-aluminum,....." &igh Temp.-High Pressures 18(1986),65-77 50003006 C.,Hornbogen E. Gefuege and the-sche Voluaenaenderungen von Al-si-Legierungen. X.Hetallkd. 80(1989),692-697 J0003018 Enjo T.,Kuroda T. 'Effect of minor alloy addition8 on aging characteristic in Al-Xn-Hg alloy welds.' Trans.JWR1 14(1985),69-76 J0003020 Enjo T.,Kuroda T. 'nicrojtructure in veld heat affected zone of Al-Hg-Si alloy. Trans.JWRI 11(1982),61-66 J0003038 FcDonald R.A.,Stull D.R. Beat content, specific heat, and heat of melting of magnesium alloy AZ-80 from 280 to 10801. J.Chem.Engng.Data 6(1961),609-610 J0003039 :amel R.,Ali A.R.,Parid Z.,El-Sal- P.A. The role of lithium atom in the structural changes of Al-Li alloy." Acta Phys.Acad.Sci.Hung. 46(1979),55-59 J0003055 Hisra R.D.K. 'A study of quenched-in vacancies in an Al-Li-Cu-Hg allo" Scr.Hetal1. 21(1987),895-899 J0003061 Swindells N.,Sykes C. 'Specific heat-temperature curves of some age-hardening alloys. Proc.Roy.Soc. A168(1938),237-264 J0003062 Fano K., fLirano K. Two step ageing in an aluminium-5wt%zinc-lwt%magnesium alloy. Trans JM 9(1968),149-156 J0003064 !ivararakrishnan C.S.,Hahanti R.K.,Kumar R. The dispersion of lead and graphite in aluminum alloys for bearing applicatione.' Wear 96(1984),121-334 J0003066 arano K.,Takagi Y. *On the precipitation process in alruinur-zinc-magnesium alloys. Part I. Al-Al2Zn3Hg3 system.' J.Phys.Soc.Japan 10(1955),187-192 50003067 hano K., fLirano K. 'Precipitation process in an Al-zn-ng alloy' Trans JM 9 (1968) ,24-34 50003069 Papazian J.H.,Bott G.G.,Shav P. .Influence of forming in the T3 condition on properties Of 2090-T8X, 2091-T8X and 8090-T8X.' J.Phys.Colloque C3 48(1987),231-237 J0003074 Papazian J.H.,Sigli C.,Sanches J.H. "New evidence for G-P zones in binary Al-LI alloy' Scripta Hetal. 20(1986),201-206 J0003075 Nozato R.,lakai G. 'Thermal analysis of precipitation in Al-Li alloys' Trana.JM 18(1977),679-689 A5

J0003076 Jo 11.4, Hirano K. "Precipitation processes in N-Cu-Lt alloy studied by DSC. " Haterials Sci.Porum 13/14(1987),377-382 J0003080 ghmudskiy A.L.,Haksimyuk P.A.,llikhrlko V.D.,Gley V.A. 'Characteriatic temperature, Young'. modulus and coefficient of linear expansion of N-Id alloys.' Phys.Met.Metallogr. 27(1969),193-195 J0003081 Elhn T.A.,Arnetrong R.W. 'Thermal expansion properties of 60fl N alloy reinforced with Sic particles or short fibres. 1nt.J.Thermophys. 9(1988),861-871 J0003100 Kapustina M.I.,Karnaushenko A.A.,Savchenko A.M.,Kuz'min !.I. Meraination of thema: and physical properties of titdm alloy 48-OT-3. &v.J.Wnferroua Metals 2(1961),73-79 J0003101 ;aragezyan A.G. Them1 diffusivity and electrical resiativity od alpha-titanium and the titanium alloys T3, TI, VT5, T6, and T8 in wide range of temperatures.' Phys.Het.Hetal1. 12(1961),39-44 J0003104 DeIasi R.,Adler P.N. "Calorimetric atudies of 7000 series aluminy alloys: I. Matrix precipitate characterization of 7075 Met.Trane 81(1977),1177-1183 J0003105 Mler P.N.,DeIasi R. "Calorimetric studies of 7000 series alumi!um alloys: 11. Comparison of 7075, 7050 and RX720 alloys. Met.Tran8 8A(1977),1185-1190 J0003106 Hirata T.,Hatsuo S. 'Effect of Ag on the precipitation processes in N-Mg-Si alloys. Trans. JIM 12(1971),101-106 J0003107 Donoso E. "Calorimetric study of the dissolution of Guieer-Preston zones and eta-phase in Al-4.5at.%Bn-1.75at.%Hg Materials Science and Engineering 74(1985),39-46 J0003 108 Elirano K. "Aging process in quenched aluminium-zinc solid solutions.' J.Phys.Soc.Japan 10(1955),995-1002 J0003109 Harkworth H. 'Anisotropie elektrischer Leitfaehigkeit bei AlXnMgCu-Legierungen" Hetall 30(1976),425-427 JOOO 3 110 ftirano X., Aeano K. Prolonged ageing of an aluminium-zinc-magnenium alloy" Trans JIM 11(1970),225-230 JO 003136 !apazian J.M. Calorimetric atudies of pxecipitition + dissolution kinetics in aluminum alloys 2219 and 7075 Met.Trans. 131(1982),761-769 JO 003137 niyaucbi T. ,mjikawa 8. ,ai'r.no 'K. 'Precipitation process of Al-Mg-Si alloys by agein' Keikinzoku(Light Metals), 21(1971),565-573 5000314 1 Redford K.,Tibballs J.E.,McPher8on R. 'Calorimetric data for rlpha-"nSi Ud the alpha-to-beta decomposition' Therpochimica Acta 158(1990),115-123 50003145 Dutta I.,Nlen S.M. "A calorimetric stud; of precipitation in commercial aluminium alloy 6061 J.Hat.Sci.Lett. 10(1991),323-326 50003148 Papazian J.H. "Effects of Sic whiskers and particles on precipitation in aluminum matrix composites' Met.Trans. 19A(1988),2945-2953 A6

50003149 Papazian J.H. 'A calorimetric study of precipitation in aluminum alloy 2219" Het.Trans. 12A(1981),269-279 J0003150 Papazian J.H. 'Differential scanning calorimetry evaluation of retrogress? and re-aged micro- structures in aluminum alloy 7075 hter.Sci.Eng. 79(1986),97-304

J0003151 Nozato R.,Ishihara 8. "Calorimetric study of precipitation process in Al-Hg alloys' Trans.JIII 21(1980),580-588 J0003152 Hirano K.,Iwasaki E. 'Calori- and resistoietric analyses of ageing and precipitation in aluminum- copper alloys' Trans.JUI 5(1964),162-170 50003163 Tye R.P.,Eayden R.W.,Spinney S.C. 'Thermal confuctivity of selected alloys at low temperatures Mvan.in Cryogenic Engng. 22(1977),136-144; Eds. Therhaus K.D.,Reed R.P.,Clark ASP., Plenum Press, New York 1977 J0003167 Piloni L.,Rocchini G. "Thermal conductivity of Inconel 600 and Ti-6Al-QV from 360K to 9OOK' High Temp.-High Pressures 21(1989),373-376 J0003168 Deem H.W.,Wood W.D.,Lucke C.P. 'The relationship between electricrl and thermal conductivities of titanium alloys. Trans.Het.&c.AIIIE 212(1958),520-523 LM!OWOOl "corn W. Cost 50" Lac0m~15.10.93 PO000008 Bogaard R.H.,Ho C.Y. 'Thermal conductivity of selected aluminum alloys - a critical review' Thermal Conductivity 19, Ed. D.W.Yarbrough, Plenum Press New York, London (1988) 551-560

PO000016 Lamvik H.,Johansen S.O. 'Thermal diffusivity and thermal conductivity of some solid metals at the melting point.' Thermal Conductivity 18, Ed.T.Ashworth,D.R.Sdth, Plenum Press New York, London (1985),723-732 PO000017 Hebed H.H,Khalek H.A.,Abd Elnaiem H.A. 'Thermal diffusivity and specific heat of commercial aluminum and aluminum copper alloys from 400 to 850K." Proc.16th Southeastern Sednar on Thermal Sciences, Miami 1982; Ed.Cora1 Gables Univ.niami 1982,p.10-12 PO000022 Butler C.P.,Inn E.C.Y. 'Thermal diffusivity of metals at elevated temperatures" Proc.Symp.on Thermal Properties,Lafayette,l959;377-390 ASWE New York,HcGraw-Hill Book Company,Inc. Hew York;1959 PO000026 Brandt van der B.,van den Brink P.J.,de Jong E.P., Katgexman L.,Kleinjan E. 'Rapid solidification processing of Al-Cu-LI-Hg alloys' Proc.2th 1nt.Conf. Aluminum-Lithium Alloys, Ilonterey(CA, USA) 1984;433-446 RLS-NKE, Warrendale,PA,1985 PO000028 Cho H.K.,Hirano K. 'Application of themallanalysis on precipitation in dilute Al-Cu-Hg alloys. Proc. 5th Int.Conf.Thema1 Analysis ICTA-5, Kyoto,Japan, August 1977 PO000029 Closset B.,Pirie K.,Gruzelski J.E. "Comparison of thermal analysis and electrical resistivity in microstructure evaluation of Al-Si foundry alloye.' Trans.of American Poundrymen's Soc. ~1.92;St.Louis 1984, p. 123-133 A7

PO000031 Closset B. 'Kicrostructural control by electrical resistivity of strontium modified alloys.' Proc.Conf.Measurement and Control in Liquid netal Processing,Prague 1986,p.53-74 Nartinus Nijhoff Publishers,Dordrecht,The Uetherl.lds,l987 PO000032 Mler P.,Geschwind G.,DeIasi R. 'Calorimetric st:dy of precipitation in a aolrercial (7075) Al alloy. Proc. 3rd 1nt.Conf. on Them1 Analysis ICTA, D.vos 1971; Birkhaeuser Verlag, -1.2, p.747-757 PO000039 Lourenco C.S.,Cilense n.,Garlipp W. 'Specific heat and resistivity of N-an-ng Nlo" Proc.37th Annual Congress (luU(vI1 Congresso Anual), Rio de Janeiro 1982,vol.l A8soc.Brasileira de Hetais, Sao Paulo,Brazil; p.521-530 PO000046 Sugfwto T.,KOMtSU S.,KaEd K. 'On the alpha/alph$+aplha2 boundary of Ti-AI.-Sn-Xr quaternary system. Proc.4th 1nt.Conf.on Titanium 19-20 MAY 1980, Kyoto, Japan; Eds.H.Maura,O.Izumi Vol.4, 2949-2957 ROO00013 Raeth C.H. 'The thermal conductivity of some project materials" UsAec Rept.CP-2332, 1-25, 1944 ROO00063 Francis E.L. 'Uranium data manual' UKAEA Rept.IGR-R/R-287, 1-51, 1958 ROO00112 Smith K.F., Chiswik H.H. 'Quarterly Report: Development of high tempefatuire strength zirconium and titanium base alloys. USAEC Rept.ANL-5257,1-18, 1954 ROO00115 Smith K.F., Chiswik H.H. "High temperature strength zirconiy ana titanium base alloys for fuel element jacketing. USAEC Rept.ANL-5339,1-15, 1956 ROO00127 Smith C.P. "Apparatus fof detednig low temperature thermal conductivity. NASA-RU(-50852,1-31,1963 ROO00128 Bollenrath P., Bungardt W. 'Weber dam Waermeleitvermoegen einiger Kolbenlegierungen bei hoeheren Temperaturen." Jahrb.Deut.Versuchsansta1t fuer Luftfahrt e.V.(1937), 348-350,1938 ROO00129 Evans J.E.Jr. 'They1 conductivity of 14 metals and alloys up to 1100P. NACA-Rn-E5OL07, 1-1511951 ROO00133 Powers R.W., Xiegler J.B., Johnston E.L. 'The thermal conductivity Of BetAls Uhd alloys at 1OV temperature -111- Data for aluminium alloy between 25 and 300K.' UMP-TR-264-7, 1-13, 1951 ROO00137 ncGee W.n.,I(etthews B.R. "Determinatizn of design data for heat treated titanips alloy sheet. UMF ASD-TDR-62-335(1962),1-413 ROO00139 Yaggee F.L.,Dumrorth R.J. "Engineering urd physica1,properties of the plutodum- lv/o aluminum fuel alloy. USAEC Rept.ANL-6330,55-58,1960 ROO00163 Lepkowski W.J.,Bolladay J.W. "The physical properties of titanium and titanium alloys' MI-= 73(1957),1-29 ROO00162 Ziegler w.T., nullins J.C. I" Final Rept. Proj.No. A-504(1961),1-54 A8

ROO00168 Suzuki T. 'On the nature of Preston-Guider atom-groups in an age-hardened aluminium-copper alloy Part I. Experimental" Sci.Rep.RITU Ser.A1(1949),183-188 TPHl2OOO fouloukian Y.S.,Mrby R.K.,Taylor R.E.,Desai P.D. Thermphysical Properties of Utter. Vol.12: Thermal Expansion - Metallic Elements and Nloys.' IFI/Plenum, New York-Washington (1975). TPsAM002 Touloukian Y.S.,Ho C.Y. 'Theraophysical properties of selected aeroapace materials..Part 11: Thermophysical properties of aeven materials. Themphysical properties of selected aerospace materials. Part II.,1977 BRANDTO1 Jaroma-Weiland G., Brandt R., Neuer G. "Theraophysical properties of light metal alloys' IKE-5-238, February 1994 L&CWOO1 hcom W., Burgholzer P. 'Aesessment of thermophysical data of aluminium alloys" OEPXS-A-2569, llay 1993 XAHRAOOl Castanet R., Zahra A.M. 'l4easurement and evaluation of theraochdcal and them- physical properties :o provide a data base for the development of new light alloys. Final Report for Project COST507, November 1992, CNRS, Centre de Theraodynamique et de Kicrocalorhetrie, narseille, France Appendix B

List of materials and properties stored in THERSYST

THC thermal conductivity THD thermal diff usivity CP specific heat capacity ENT ent ha I p y ELR electrical resistivity LOR Lorenz number LEX linear thermal expansion VEX volumentric thermal expansion DEN density ABS absorptance EM1 emittance TRA transmittance REF reflectance ACO absorption coefficient RIN refractive index EXT extinction coefficient E1

THERSYST 5.01.94 ------SHORT PROPERTIES THC THD CP SUU .----- NULL aluminum 111 6 BOALBEOO aluminium-beryllium alloy 1-- 7 BOALCUO 0 aluminum-copper alloy 46 - 42 115 BOALFEOO aluminium-iron alloy 6-2 14 BOALLIOO aluminum-lithium alloy .. - 32 36 BOAXJIGO 0 aluminium-magnesium alloy 16 - 29 57 BOALlINO 0 aluminum-manganese alloy 5-- 5 BOWlOO 0 aluminium-molybdenum alloy --- 2 BOALNIO 0 aluminium-nickel alloy 3-3 6 BOALPUO 0 aluminum-plutonium alloy 1-- 1 BOALSIOO aluminium-silicon alloy 2-6 36 BOALSIOl Silumin, aluminum-silicon alloy 1-- 1 BOALSIO2 Nusil, aluminum-silicon alloy 1-- 2 BOALTIOO aluminium-titanium alloy 11 6 6 26 BOALUQOO aluminium-uranium alloy 2-- 6 BOALZNOO aluminum-zinc alloy 2 1 34 39 BOALZROO aluminium-zirconium alloy 2-- 6 COALBEOl Lockalloy --- 4 aluminium-beryllium-sum(x)-alloy COALCUOO aluminum-copper-sum(x) alloy 722 11 COALCUO 1 AA-2018, aluminum-copper-sum(x) alloy 2 COALCUO 2 AA-2017, aluminum-copper-sum(x) alloy -13 6 COALCU03 Ah-2014, M-145 411 9 aluminum-copper-eum(x) alloy COALCU04 M-2024, AA-24s 11 9 10 -- 8 38 aluminum-copper-magnesium-aum(x) alloy - - 31 COALCU05 M-2025, As= B 247 2 aluminum-copper-sum(x) alloy COALCU06 M-2020, aluminum-copper-sum(x) alloy ------2 - 2 COALCU07 Y-alloy 3-- 7 aluminum-copper-magnesium-mm(x) alloy COALCUOB Russian V-65 --- 2 coALcuo9 Russian D-16 --- 2 COALCUIO Tempaloy 841 --- 2 COrnUll An-2219 1 - 30 31 aluminum-copper-manganese-sum(x) alloy COALCUl2 aluminum-copper-magnesium-sum(x) alloy 3 1 22 29 COALCU13 aluminum-copper-nickel-sum(x) alloy 30 - - 10 COALCU14 aluminum-copper-iron-sum(x) alloy 3-- 3 COALCU15 aluminum-copper-silicon-sum(x) alloy 1 - 15 16 COALCU16 aluminum-copper-silver-sum(x) alloy 2-- 3 COALCUl7 aluminum-copper-manganese-sum(x) alloy 1-- 1 COALCUl8 AK6, aluminum-copper-silicon-sum(x) 1-- 1 cornu19 IVL-2124 --6 6 aluminium-copper-magnesium-sum(x) COALCUIO D20, aluminum-copper-sum(x) alloy 1-- --- coALCu21 M-2090 --E - - -I aluPinum-copper-lithium-mum(x) alloy coALCu22 M-2091 --4 aluminum-copper-lithium-sum(x) alloy COALCU23 Duralumin --2 ------I aluminum-copper-aagnesium-sum(x) alloy COALcU2 4 aluminum-copper-lithium-sum(x) alloy --3 COALCU25 RR 350, aluminium-copper-nickel-.ur(x) 1-- -12 COALCU26 Eontal 8 1-- -12 rluminium-copper-rg~e~e-~um(x) - COALPEOI aluminium-iron-silicon alloy - 2-- 2' COALpEQ2 All 100-P -1------I 1 alurinur-iron-silicon-.ur(x) alloy COlLtLIO 1 aluminium-lithiur-coppar-aur(x) alloy 111- 8 COALL102 M-8090, LITAL A, CP 271 20 2 5 -22 31 COAIWGOO aluminur-magneaium-mum(x) alloy I-- -1- 5 COAU(G0 1 M-6061 4 2 12 -17 26 aluminum-~gneeiur-~llicon-mum(x) alloy CONJtGO 2 M-6053 -- 2 2 aluminum-magnesium-su(x) alloy COAXJIG03 M-5052 1-3 --2 6 aluminum-magnesium-sum(x) alloy COAXJIG04 M-5083 --2 4 aluminum-magnesium-sum(x) alloy COAIWGO5 M-5456 l-- 3 aluminum-magnesium-sum(x) alloy COAXJIG06 J51 alloy 1-- --- 1 aluminum-magnesium-sum(x) alloy COAXJIG07 aluminum-magnesium-silicon alloy 4 - 41 -4- 49 B2

COAIHGO8 wg5 1 aluminuP-ragnesium-ug~e6e-6um(x) coIwGo9 M-5754 15 aluminum-magnesium-manganese-sum(x) COAUIGlO AE-80, magnesium-aluminum-sum(x) alloy 2 COAIHGl1 aluminum-magnesium-zfnc-.um(x) alloy 17 CONJIG12 M-6063 3 rlurlnum-Mgne6ium-6ilicon-.ur(x) alloy COAIHG13 M-5251 3 aluminium-magnesium-rangane6e-mum(x) COAIHG14 M-5086 2 aluminium-ragnesium-~g~e6e-sum(x) COAIMNO 1 M-3003 (Alcoa 3s) 2 aluminum-manganese-.ua(x) alloy COAIMNOZ M-3004, 4 S alloy 1 aluafnum-manganese-sum(x) alloy COAIMN03 Antes, aluainum-manganese-mum(x) alloy 1 COAIIM04 aluminium-manganese-silicon-sum(x) allo 1 COAmBO 1 aluminium-niobium-germaniua-6um(x) all0 i COALNIOO aluminium-nickel-sum(x) alloy 2 COALNI01 aluminium-nickel-iron EWI(X) alloy 3 COz4IJNI02 aluminium-nickel-mangane6e-Eum(x) alloy 1 COALS100 aluminium-silicon-aum(x) alloy 5 c0AcG101 M-6151, aluminum-silicon-sum(x) alloy 2 COALS102 M-4032, aluminum-silicon-sum(x) alloy 2 COALS103 M-355, aluminum-silicon-sum(x) alloy 2 COALS104 aluminum-silicon-copper-sum(x) alloy 10 COALS105 Silumin, aluminum-silicon-sum(x) alloy 2 COALS106 M-6082 13 aluminium-silicon-magnesium-6um(x) COALS107 rluminum-6ilicon-aagneaium-6um(x) 4 3.2384.6 COALS108 AA-390 4 aluminum-silicon-copper-sum(x) alloy COALS109 aluminum-ailicon-magnesium-sum(x) 5 COALSIlO aluminum-silicon-lead-sum(x) 2 COALS111 A356.0 10 aluminum-silicon-magnesiua-mum(x) alloy COALS112 A357.0 2 aluminum-silicon-magnesium-aum(x) alloy COALS113 M-6060 7 aluminum-silicon-magnesium-sum(x) COALS114 KS 1275 4 aluminum-silicon-copper-magnesium-sum(x COALS115 AA-6 0 0 SA 2 aluminum-silicon-magnesium-sum(x) alloy COALTIOO aluminium-titanium-sum(x) alloy 9 COALTI01 aluminium-titanium-rolyMenum- 6um (x) 8 COALTI02 aluminium-titaniua-tin-zfrconium-6um(x) 5 COALTIO3 aluminium-titanium-v~adium-Eum(x) allo 25 C OALTI 04 Rylite 4 aluminum-titanium-tin-zirconium-sum(x) COUTI05 OT-4, titanium-aluminum-sum(x) alloy 3 COALTI0 6 VT-20, titanium-aluminum-sum(x) alloy 1 COALTI07 VT-9, titanium-aluminum-su(x) alloy 2 COALTI08 VT-18U 1 titanium-aluminur-zirconi~Eum(x) COALTI09 TI6Al4V1 Tikrutan LT 31 25 titaaiun-aluainiua-vanadium-6um(x) COALTI10 VT-3 1 titanium-aluminum-chromium-mum(x) alloy COALTI11 VT-5, titanium-aluminum-sum(x) alloy 11 ' COALTI12 VT-14 1 titanium-rluminuP-mlyMenum-6um(x) COALTI13 VT-5-1 1 titanium-aluminum-tin-Eum(x) alloy COALTI14 Ti-All0 AT 6 titanium-aluminum-tin-.ur(x) alloy COALTI15 VT- 6 2 titanium-al~num-vanadium-E~(x)alloy COALTI16 VT-8 7 titanium-aluminum-roly~enua-clum(x) COALTI17 TS-5 2 titanium-aluminum-vanadium-sum(x) alloy COALTI18 TiAl5Sn2, 3.7115 1 titanium-alirinum-vanadiua-.ur(x) alloy COALTI19 PT-3V 5 titanaium-aluminum-vanadium-sum(x) COALTI 20 VT-1-0, titanium-aluPinium-sum(x) 5 COALTI21 Tikrutan LT33 2 SHORT ------.------THCRIDCP ENTELRLEX I sm COALTI22 C-130- 1---1- 2 titanium-aluainum-~g~ese-sum(x) COALTI24 Ti-l55A, titanium-aldnum-iron-sum(x) 1 - - - 1- 2 COALXNOO aluminum-zinc-sum(x) alloy 2----- 2 COALXNOl M-7039, aluainum-zinc-sum(x) alloy 2---12 5 COALXNOZ M-7075, M-758 8 3 39 - 10 10 70 aluminum-zinc-ragnesium-coppsr-.ru(x) AlXnl4gCu 1.5 ? 53, PWDlOAt215 COALXNO3 M-7079, aluainup-zinc-sum(x) alloy -----2 2 COALXNO4 aluminum-zinc-copper-sum(x) alloy I----- 1 COALXN05 aluminum-zinc-magnesium-sum(x) alloy 1 - 117 - 20 - 138 COALXNO6 M-7010 -36--2 11 aluminium-zinc-~gnesium-copper-sum(x) COALXNO7 M-7020 -26--- 8 aluminum-zinc-ragnesium-sum(x) alloy COALXNOB M-7050 --4--- 4 aluminum-zinc-copper-~gnesi~sum(x) COALXN09 RX720 -- 2--- 2 aluminum-zinc-magnesium-copper-mm(x) COALXNIO M-7009 ----6- 6 aluminum-zinc-ragnesium-copper-sum(x) COALXNll M-7109 ---- 6- 6 aluminum-zinc-magnesium-copper-sum(x) COAL1112 M-7475 --2--- 2 aluminum-zinc-magnesium-copper-sum(x) COALXN13 Titanal -15--3 9 aluainium-zinc-magnesi~copper-sur(x) COALXRO 1 aluminum-zirconium-tin alloy 3----- 3 COTIVQOl titanium-vanadium-aluminium-mm(x) a110 - - 1 1 - - 2 VllALOALO al~dum/Al203,8i02composite -- 1-- 3 4 aluminium/Altex composite WAWALl Al203/KS1275 composite 16 8 2 - - - 26 vnALoAL2 h1203/M-6061 composite 336--5 17 WQALO aluminium/carbon composite --1--2 3 VlISICALO aldnium/ailicon carbide composite --1--3 4 alddum/Nicalon composite VlISICALl SiC/M-2124 composite --I--- 4 vnsICAL2 SiC/M-2219 composite --I--- 1 WICAL3 M-6061/SiC composite --3--8 11 vIIsICAL4 SiC/AA-7475 composite --2--- 2 vwSICAL5------.------SiC/A-356 composite -12-- 1 4 290 85 596 8 147 199 I 1325