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Masters Theses Student Theses and Dissertations

1940

Constitution and properties of manganese- alloys

James Harrison Jacobs

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Recommended Citation Jacobs, James Harrison, "Constitution and properties of manganese-copper alloys" (1940). Masters Theses. 4747. https://scholarsmine.mst.edu/masters_theses/4747

This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. CONSTITUTION AND PROPERTIES OF MANGANESE-COPPER ALLOYS

By

JAME~ HARRISON JACOBS

A THESIS submitted to the Faculty of the SCHOOL OF MINES AND METALLURGY OF THE UNIVERSITY OF MISSOURI in partial fulfillment of the work required for the Degree of MASTER OF SCIENCE IN METALLURGICAL ENGINEERING

Rolla, Missouri 1940

~ _~_.--=:--_Ci>=--_~--::~:=-.. ~::-::---;---{'r-­ Approved by Charles~ Professor of Metallurgical Engineering and Dressing I.

TABLE OF CONTENTS

Page List of Illustrations II

Introduction 1 Survey of Literature 3 Preparation of Alloys 16 Heat Treatment 18 Effect of Cold Work 21 Coefficient of Expansion 23 Vibration Damping Capacity 26 Electrical Resistanc'e 28 Hardness 34 Preparation of Specimens for Photomicrography 40 Microstructure 45 Discussion of Results 50 Sunmary 54 Acknowledgment 55 Bibliography 56 Index 58, 59 II

LIST OF ILLUSTRATIONS

Page Fig. 1 Constitutional Diagram of Manganese­ Copper Alloys as Determined by Ishiwara 6 Fig. 2 Lattice Parameters of Manganese- Copper Alloys 6 Fig. 3 Constitutional Diagram of Manganese­ Copper Alloys Taken From a Compilation by Hansen 8 Fig. 4 Effect of Temperature on the Electrical Resistance of Mangan- ese-Copper Alloys 30 Fig. 5 Effect of Composition on the Electrical Resistance of Manganese­ Copper Alloys heated at Various Temperatures 33 Fig. 6 Effect of Quenching Temperature on the Hardness of Manganese-Copper Alloys 36 Fig. 7 Effect of Composition on the Hardness of Manganese-Copper Alloys Heated at Various Temperatures 38 Fig. 8 Micro-structure of Manganese-Copper Alloys after Various Heat Treatments ~ Fig. 9 Micro-structure of Willnganese-Copper Alloys After Various Heat Treatments 47 Fig. 10 Hardness and Electrical Resistance of Various Manganese-Copper Alloys After Quenching from Different Temperatures 51 Fig. 11 Hardness and Electrical Resistance of Various Manganese-Copper Alloys After Quenching from Different Temperatures 52 1.

Introduction

This work was undertaken because of the recently revived interest in the use of manganese as an ­ ing element. This revival of interest has been mainly due to the development of the process for electro­ deposition of manganese by the U. S. Bureau of Mines. Prior to the work of the Bureau of Mines there was no commercial source of high purity manganese. Manganese made by the electrolytic process contains less than .03% impurities, while manganese made by other methods contains as high as 3% impurities. The use of high purity manganese as a base for alloys should open up an entirely new field of non­ ferrous metallurgy, since the small amount of prelim­ inary work that has already been done indicates the possibility of the development of alloys having pro­ perties hitherto unknown to non-ferrous alloys. The manganese-copper system was chosen for study because the literature is extremely controversial with regard to this system. The alloys that were examined contained 50-96% manganese. Alloys contain­ ing less than 50% manganese were not investigated because previous work has shoi~ them to undergo little change with heat treatment. The various alloys were subjected to thermal treatments and the hardness, coefficient of expansion and specific electrical resistance determined. They were also examined under the microscope and photo­ graphed. 3.

Survey of Previous Work on the Manganese-Copper System

Constitution- Copper-manganese alloys were examined as early as 1870, but E. A. Lewis (l)made

(1) E. A. Lewis: Alloys of Manganese and Copper, Journal Society Chem. Ind., Vol. 21, 1902, pp. 842-844. the first attempt to determine the constitution of the alloys. He found a marked minimum in the liquids at 47% manganese which he interpreted as a eutectic point. S. Wologdine (2) then published a diagram with a mimimum at 40% manganese and a maximum at 78% manganese corresponding to the compound Mn Cu. Later investigators have dis~roved this compound definitely, and it is probable that Wologdinels thermal arrests were due to absorbed . (3) In 1908 the diagrams of Sahmen and Zemczuzny, Urascow and RYkowSkow(4)were published, both of which

(2) Wologdine, S., Alloys of Manganese and Copper: Rev. Metallurgy, Vol. 4, 1907, pp. 25-38. (3) Sahmen, R., !lloys of Copper with Cobalt, , Manganese, and ~fugnesium: Zeit. Anorg. Chemie, Vol. 57, 1908, pp. 1-33. (4) Zemczuzny, S. F., Urasow, G., and Rykowskow, A., Alloys of Manganese with Copper and :Zeit. Anorg. Chemie, Vol. 57, 1908, pp. 253-261. 4.

showed a continuous series of solutions. Sahmen placed the minimum at 35% Manganese and 866°c, while Zemczyzny placed the minimum at 30.3% manganese and 868°C. The diagrams agreed closely on the copper­ rich side of the minimum, and, although there was a difference between the liquidus temperatures on the manganese side, the principal difference was in the solidus. Sahmen showed the liquidus to be pra~tically horizontal up to 70%, while Zemczuzny showed the solidus to rise close to the liquidus.

Both men claimed that the alloys could b~ rendered microscopically homogeneous. The thermal investi- gations of Sahmen on the liquidus and solidus have been checked by later work, and are now considered to be nearly correct. All of the early investigators considered the manganese-copper system to be a continuous series of solid solutions, and this persisted in the liter­ ature despite the x-ray work of Bain(5)and of Patterson (6).

(5) Bain, E. c., of Solid Solutions, Trans. A.I.M.E., Vol. 63, 1923, pp. 625 (6) Patterson, R., Crystal Structure of Copper Manganese Alloys: Phys.Rev.,Vol. 23, 1924,pp.552 :i.

They found the manganese lines to appear on the x-ray diffraction patterns of the alloys at 50-60% manganese, which showed the definite heterogeneity of the solid alloys throughout much of the range. This difference from the original diagram was also noted by corson(7) and Smith (8), who placed the solubility limit at 8000 at 30%.

(7) Corson, M. G., Manganese in Non-Ferrous Alloys, Trans. A.I.M.E., Inst. Div., Vol. 78, 1928, pp. 483. (8) Smith, C. S., Alpha- Boundary of the Ternary System Copper-Silicon-Manganese: Trans. A.I.M.E., Inst. Metals Div., Vol. 89, 1930, pp. 164.

The discovery of the allotropy of manganese emphasized the need for a revision of the diagram, and this was done by Ishiwara (9,10). This diagram

(9) Ishiwara, T., Equilibrium Diagrams of the Aluminum-Manganese, Copper-Manganese and Iron­ Manganese Systems: World Eng. Congr., 1929, Paper No. 223. (10) Ishiwara, T., On the Equilibrium Diagrams of the Aluminum-Manganese, Copper-!J[anganese and Iron­ Manganese Systems: Tohoku Imp. Univ., Soc. Repts., 1930, Sere 1, Vol. 19, pp. 499. showed the heterogeneous areas, and is shown in Fig.l. 6 ..

1100 r---+--4-t--+-----:;;J""9--~

7001--W~t===t===+=~ 01.-+ c<. Mn

~ 0 0 1----+4l-.---+--+---+----f

O'--_...... _--L__..L-._---'-_----" 20 40 60 80 100

MAN GANESE BY WEIGHT % J

COPPER-MANGANESE: CONSTITUTION DIAGRAM BY I.5HIWARA FIGURE I

3.800 r---~---"T--"""'-----'------'l

3.700 I-----+~~---+-----I..l~--f

3.600 ~---+-----+---+----+--'\--t

3.500 L...-_-l--_--L__....L.-_---'-_----" o 20 40 60 80 100

% MANGANESE BY WEIGHT

LATTICE PARAMETER OF COPPER-~AN6ANESE ALLOYS

FIGURE 2 (11) (12) Persson and Ohman and Sekito , however, showed

(11) Persson, E., and Ohman, E., A High-Temperature Modification of Manganese: Nature, Vol. 124, 1929, pp. 333. . (12) Sekito, S., Z. Kristallographie, Vol. 72, 1929, pp. 406. that it was not impossible for copper and gamma manganese, stable at high temperatures, to be isomor- phous. The lattice parameters of the alloys quenched (13) from suitable temperatures, as determined by Persson

(13) Persson, E., X-Ray Analysis of the Copper­ Manganese Alloys: Z Physik. Chern., Abt. B., Vol. 9, 1932, pp. 25-42. are shown ih Fig. 2. Persson obtained the alpha boundary shown in the equilibrium diagram, Fig. 3, by comparing the lattice parameters of alloys quenched from 400, 500 and 600oc. From Persson's work the alloys have the structure of gamma manganese, as quenched, up to 18% copper. At this point the axial ratio of the tetragonal manganese becomes unity and is therefore isomorphous with the copper phase. Persson found no solubility of copper in the beta or 1300 r------_--,

1244 1200 1181 I1~T LI QUID

1100 / IO&) / / / 1000 / / / / ______~...,.I-( /f

900 L1QUI D + 0 _ - I I ___ ---- I I -..-.-_--__---- I I 7 r jJ :I o ~7 II/ 800 ""---1 / II/ II 1~-;i9 ---- lUa < 700 a: ....."- Z lU u 600

Vl lu W a: 500 d'+ «. w 0" rX 4 00

300

200 L- .L... ~ a 10 20 30 • 0 ~ 0 {) 0 7 a 8 0 ~ 0 100 PERCENT MANGANESE

FIgure 3- Equll ibrlum diagram of manganese-copper alloys. 9.

alpha lattices as indicated by the lattice parameters. Valentiner and Becker(14) obtained results for the

(14) Valentiner, S., and Becker, G., Susceptibility and Electrical Conductivity of Copper Manganese Alloys; Z. Physik, Vol. 80, 1933, pp. 735-754. lattice parameters that were in agreement with the work of Persson. (15) C. S. Smith seems to think that the results

(15) Smith, C. S., Metals Handbook, 1939, pp. 1350 of Persson on the lattice parameter can be interpre­ tated to indicate a sloping curve up to 40% manganese intersecting a horizontal stra.ight line at this point. If this were true, the solubility of manganese in copper would be about 40% and between 40 and 80% manganese there would coexist two phases of almost identical structure, possibly with a difference in the location of the copper and manganese atoms in the gamma lattice. Va1entiner and Becker, using commercial manganese, heated alloys to 7500 for 15 hours, quenched, and then 10.

aged them at 3500 for 48 hours. They found that alloys containing more than 60% manganese had in­ creasing amounts of beta manganese in them. These results are in complete disagreement with Persson's work. If Persson's diagram were correct, the alloys should have been almost completely alpha manganese. Broniewski and Jaslan (16) studied alloys that

(16) Broniewski, W., and Jaslan, S., Alloys of Copper with Manganese: Am. Acad. Sci. Tech. Varsovie, Vol. 3, 1936, PP. 141-154.

were annealed at 6000 after quenching from 8000 , 9000 and 10000 C. They found that up to 20% manganese the alloys were homogeneous with all heat treatments. Alloys with more than 20% manganese show traces of a second phase high in manganese in the annealed, but not in the quenched state. Alloys with more than 30% manganese quenched from 8000 C showed two metallographic constituents, - one high in copper, the other high in manganese. On annealing there is a refinement by the partial decomposition of both constituents. Quenching from 9000 C renders an alloy of 85% manganese homogeneous. The entectoidal transformation of the solid solution high in manganese was especially 11.

visible in an alloy of 90% manganese that was cooled in the furnace from 1030oC. lshiwara, using 96 to 98% manganese, found that an 80% manganese alloy was homogeneous after being heated at 8400 C for a week, but was two phase after being heated to 825 0 C for a week. This result is not in accord with the accepted diagram. Broniewski and Jaslan put forth a diagram that was very similar to that of lshiwara's. Electrical Resistance:- Zemczuzny performed the earliest work upon the electrical resistance of this series of alloys, but his results are of little importance. Hunter and Sebast (17) determined the

(17) Hunter, M. A., and Sebast, F~ M., The Electrical Properties of Some High Resistance Alloys: J. Am. lnst. Metals, Vol. 11, 1917-18, pp. 115-138. electrical resistance of alloys up to 60% manganese and found that the resistance approached a maximum of about 140 x 10-6 ohms per cm3 at 60% manganese. Broniewski and Jaslan, using alloys made of commercial manganese that were cast in a mold 5 roW- in diameter and 15 rom. long and annealed 7 days at 500°C, found a uniform increase in resistance from 12.

copper to a resistance of 164 x 10-6 ohms per cm3 for the grade of manganese used. Korenev (18) found

(18) Korenev, N. I., Alloys of Manganese With Copper: Am. Secteur, Analy. Phys. Chern., Inst. Chern. Gen. (U.S.S.R.) Vol. 11, 1938, pp. 47-63. values for the electrical resistance of these alloys that were nearly in agreement with those determined by Broniewski. He also found, however, that the electrical resistance was increased by the eliminat­ ion of impurities such as AI, Fe and Si, and also depended upon the thermal treatment. Valentiner and Becker measured the resistance of alloys made with impure manganese and copper and obtained values that 6 ranged from 31 x 10- ohms per cm3 at 10 atomic per- 6 cent manganese to 173 x 10- ohms per cm3 at 90 atomic percent manganese. Dean (19) and co-workers have found that the

(19) Dean, R. S., Anderson, C. T., Moss, C., and Ambrose, P.M., U. S. Bureau of Mines, R. I. 3477, November 1939. electrical properties of copper-manganese alloys, 13.

made from pure electrolytic manganese are quite different from those previously reported by other investigators for alloys made from commercial mangan­ ese. They found a considerable range of resistance reaching a maximum of nearly 200 x 10-6 ohms per cm3 at 65% manganese for the alloys quenched from near the solidus. The resistance was greatly de­ creased when the alloys were reheated to 5000 C. Coefficient of Expansion:- Broniewski and Jaslan determdned the coefficient of expansion of the copper-manganese and found values ranging from 15.9 x 10-6 em. per em. per 0 C for copper to 18.6 x 10-6 cm. per em. per °c for the alloy containing (20) 800%manganese. Krings, and Ostmann found an expansion followed by a contraction on cooling the alloys high in manganese and interpreted this

(20) Krings, W. and Ostmann, W., The Ternary System Copper-Aluminum-Manganese and its Magnetic Properties: ztschr. Anorg. Allgem. Chern., Vol. 163, 1927, pp. 145-164. as a transition in the alloy. Mechanical Properties: - Very little work has been done upon the mechanical properties of 14.

manganese-copper alloys because, with the exception of the alloys of Zemczuzny, no alloys of more than 60% manganese have been found ductile enough to work into suitable form for their determination. This has undoubtedly been due to the fact that nearly every investigator has used commercial manganese containing as high as 3% impurities for the prepara­ tion of the alloys. Corson reported the Brinell hardness of alloys from 10 to 60% manganese to be 125 to 150. The hardness was reduced by quenching from BOOoC and reheating to 450oC. Perrson used pure manganese-copper alloys, but made only the qualitative statement that alloys containing as low (21) as 5% copper were quite malleable. Kroll , using twice distilled manganese, found that the 85%

(21) Kroll, W., Hot Workable Manganese and its Ductile Alloys: Ztschr. Metall., Vol. 31 (II) January 1939, pp. 20-23. manganese alloy quenched from 9000 C remained ductile o (19) up to 500 C. Dean and his co-workers found, however, that the entire series of manganese-copper alloys as high as 96% manganese could be both hot 15.

and cold worked in small sections. The alloys were made from pure electrolytic manganese, which is the reason advanced for their ductility. Hardness: - Very little work has been reported in the literature upon the hardness of manganese­ copper alloys. Broniewski and Jaslan found the hardness to increase gradually from 51.5 Brinell for pure copper to 741 Brinell for commercial manganese when the alloys were annealed at 600oc. When quenched from 8000 C the Brinell hardness increased from 51.2 for a 2% manganese alloy to 410 for a 95% manganese alloy. Dean found that the alloys made from electrolytic manganese and quenched from near the solidus increased from -35. Rockwell nc" hardness for the alloys containing low percentages of manganese to -10 Rockwell "c" for the alloy containing 96% manganese. When the quenched alloys were reheated to 5000 C the hardness increased from -35 Rockwell "C" to .;. 50 Rockvlell nc" for the 96% manganese alloy. Dean attributes this remarkable hardening to ordering. He also found that the quenched alloys were hardened by cold work. 16.

Preparation of the Alloys The alloys were prepared from electrolytic manganese containing less than .03% impurities and pure copper shot. They were made by melting the proper amounts of manganese and copper in an induction furnace using an alundum crucible. The alloys were not deoxidized and no flux was used. They were cast in a copper chill mold in ingots 5/8 inches in diameter and four inches in length. After the alloys were cast they were turned down slightly in a lathe to remove inclusions and pits. They were then hot worked to break down the dendritic structure which results from casting. After being hot worked the alloys were quenched from just below the solidus and then cold worked in a swaging machine to rods of about .20 inches diameter. In working down the rods it was necessary to soften them several times by reheating to just below the solidus and quenching because they became diffi­ cult to work due to hardening. The numbers and analysis of the alloys used are shown in Table I. 17.

TABLE I

Percent Number Manganese K-23 96 K-25 92 K-26 90 K-29 82.5 K-31 75 K-19 70 K-17 60 K-32 50

The alloys were cut into six inch lengths for subsequent treatment and examination. Heat Treatment Ordinary methods of heat treatment could not be utilized with these alloys, especially at high temperatures, because of the rapid oxidation which they undergo at elevated temperatures. The alloys do not form a unii"orm scale when heated in air, as does, but become badly corroded and pitted, leaving a very uneven cross-section. Since it is necessary to have a uniform surface and cross-section to determine hardness and electrical resistance it was necessary to devise a method of heat treating the alloys in absence of air. Since it was known from past experience with these alloys that they absorb carbon, nitrogen and boron they could not be heated under carbon or borax or in a nitrogen or hydrocarbon atmosphere. The first attempt to heat-treat the alloys was to place them in a silica tube sealed at one end. The other end of the tube was connected to a vacuum pump, and the tube then inserted in a Hayes furnace. When the alloys were heated in the vacuum at 950°C or above they still became corroded and pitted, and the walls of the silica tube became coated with a dark bro~n film. This film was analyzed and contain- ed about 90% manganese, indicating that manganese had sublimed from the alloys and condensed on the walls of the silica tube. Apparently the vapor pressure of copper-manganese alloys at high temper­ atures is too great to allow them to be heated in a vacuum. Heat treating in a vacuum was then abandoned and a tank of helium was substituted for the vacuum pump. Several preliminary experiments indicated that the alloys could be heated successfully in a helium atmosphere and this was the method used for all thermal treatments of the alloys. The alloys were placed in a silica tube of

I 3/4t1 inside diameter having one end sealed. A rubber stopper containing an inlet and outlet glass tube was placed in the open end of the silica tube. The helium was passed directly into the tube, and out the outlet tube into a small flask of . The mercury was used to give a slight back pressure so that the flow of helium could be regulated. The silica tube containing the alloys was heated in a Hayes furnace. All of the alloys were heated for two hours at a temperature near the solidus and then allowed to 20.

cool in the tube until room temperature was reched • This required about five hours, and these are the alloys that are called slow cooled in this discussion. After the alloys had been slow cooled, a differ­ ent rod of each alloy was taken for each heat treat­ ment. The alloys were then heated for two hours at various temperatures and quenched in water.

Although manganese-copper alloys are kno~~ to be sluggish, they were heated only two hours at each temperature because of lack of time and equip­ ment. 21.

Effect of Cold Work on Manganese~Copper Alloys

In order to determine the effect of cold work upon manganese-copper alloys, the hardness and electrical resistance of the rods were measured after quenching from near the solidus. The alloys were then reduced approximately 50% in a swaging machine and the above properties again measured. Cold work increases the hardness of the high copper alloys and has only a slight effect upon the alloys high in manganese. The 50% manganese alloy was increased from -33 Rockwell lICII hardness to ';'3 Rockwell ncn, while the 96% alloy was increased from -23 Rockvvell nClI to -6RocIDvell IICfl. The inter- mediate alloys, from the highest to the lowest copper content, showed a gradually decreasing effect of cold work upon the hardness. Cold work was found to have little or no effect upon the electrical resistance of the alloys contain­ ing more than 75% manganese. The alloys between 50% and 75% manganese showed an increase in resistance varying from 25 x 10-6 ohms for the 50% alloy to 8 x 10-6 ohms for the 70% alloy. The effect of cold work on the resistance can be explained by the assumption that cold work increases 22.

the tendency of the alloys below 80% manganese to disorder, thereby increasing the resistance. 23.

Coefficient of Expansion

The coefficient of expansion of the alloys was determined using a Rocbvell dilatometer. The speci­ mens were prepared by machining an ingot, 6 inches long and 1/2 inch in diameter, to a uniform cross section. All of the specimens were slow cooled from near the solidus before the expansion was determined. The experimental values for the coefficient of expansion of the various alloys are shown in Table II. The expansion of all of the alloys was greater at high temperatures than at low temperatures, thereby causing the mean coefficient of expansion to be higher the greater the range of temperature. The general

trend of the coefficient of expansion is do~~ward with a decrease in manganese content indicating that the manganese is the chief contributing factor to the unusually high expansion of these alloys. These alloys have expansions several times that of steel and most common non-ferrous alloys and should, therefore, be useful in the field where a high expansion is desired. None of the alloys showed any contractions as they were heated from room temperature to near the solidus, indicating that any transitions that take 24.

TABLE II

Coefficient of Expansion of Manganese-Copper Alloys

Temperature of 96% Mn. 92% lllIn. 90% MD. 82.5% Mn. 80- 400 17.7xlO-6 16.8xlO-6 14.9xlO-6 14.7xlO-6 80- 800 11·4 22.4 21.4, 23.0 80-1200 12.4 23.9 24·2 25.3 80-1600 22.1 24.8 24.8 24.3 80-1800 23.7 24.$ 24.7

Temperature CtF 75% Mn. 70% Mn. 60% Mn. 50% Mn. --~., -6 80- 400 13.3x10-6 15.9xlO 6 80- 500 16.9x10- 80- 800 19.4 17.0x10-6 17.0 80- 900 23.2 80-1200 26.0 25.3 21.9 80-1300 26.3 80-1500 26.6 24·2 22.1 80-1600 24·2 25.

place within the alloys do so with little or no change in volume. Since these alloys are sluggish it would not be expected to find any contractions on a relatively fast heating rate as used to deter­ mine the coefficient of expansion. The 96% manganese alloy, when quenched from near the solidus and heated in the dilatometer, showed a large contraction at 7500 to 8000 F followed by ex­ pansion on further heating. This contraction was probably due to the change from gamma to alpha manganese. The temperature of the breakdown of the gamma solid solution depends greatly upon the time and temperature of heating near the solidus. 26.

Vibration Damping Capacity

Previous investigators of manganese-copper and other manganese alloys have made no mention of the fact that these alloys have an unusually high vibra- (19) . tion damping capacity. Dean , however, did observe this property when working with alloys made from pure electrolytic manganese and reported measure­ ments for various alloys. He found that copper­ manganese alloys, when properly treated, had a vibra­ tion damping capacity many times that of common ferrous or non-ferrous alloys and approached the value of lead. In this investigation facilities were not avail- able for the quantitative measurement of the vibra- tion damping capacity of these alloys, but a quali­ tative determination was made on the alloys in various states by observing the amount of ring produced by dropping the alloys on a concrete surface. The 96% alloy possessed a definite ring in the slow cooled state, and this ring persisted throughout the range of heat treatment until BOOoC was reached. At this temperature the ring began to decrease and at a temperature near the solidus the alloy showed a maximum damping capacity. The 92% and 90% manganese alloys exhibited a ring in the slow cooled state and the ring persisted throughout the entire range of heating. They did show a minimum of ring, however, at temperatures above 900°C. The 82.5% alloy, when slow cooled, was very dead. At 6000 c and 700°C the alloy was still slightly dead. As the temperatuxe was further increased the damping of the alloy again increased. This alloy possessed the greatest damping capacity of all the alloys. The 75%, 70%, and 60% manganese alloys showed a minimum of damping in the slow cooled state. The deadness, although not very distinct, became a ring at 600°C and this ring increased up to the solidus. The 50% alloy had a ring in the slow cooled state and this persisted up to 700°C. At 7000 C the alloy was very dead and as the temperature was increased to the solidus this deadness gradually gave way to a ring again. Although these results on damping capacity are admittedly very qualitative and depend entirely upon the personal element, it is believed that they are of value in that they do show definite trends in the alloys. 28.

Electrical Resistance

Method of Measuring Resistance:- The electrical resistance of the alloys was measured by the potential drop method using a type K potentiometer. The rod to be measured was suspended upon knife-edges to insure a good contact and a uniform length for each alloy measured. A manganese-copper rod of known resistance was used as a standard for comparison with the unknown specimen. The standard and unknovm rods were connected in series with a variable resistance and a stor~ge battery and the potential drop across each rod measured. After the potential drop has been measured the resistance of the unknown rod can be calculated by direct proportion. All of the measure- ments we-c'e made at room temperature and the results were reproiucible within 2%. Resistance of the Alloys after Various Thermal Treatments:- In Table III are given the experimental values of the specific electrical resistance of the alloys in~~~eral states. Figure 4 shows the change of resistance. of the various alloys with quenching temperature. At first glance the most striking effect is the lack··of"_ all the alloys, vtith the possible exception 0' the 96% alloy, to change in resistance Table III Electrical Resistance of Manganese-Copper Alloys Specific Resistance x 106 2 hours at Slow 0 0 %Mn. Cooled 3000 4000 500 5500 6000 7000 7500 8000 8500 9000 10000 1040 96 120.4 111.2 115.0 116.5 116.0 126.1 125.2 168.1 147.0149.1 116.7 83.0 78.7 92 102.0 102.9 103.1 101.4 100.2 108.2 119.1 123.8 117.2102.4 101.2 101.3

90 102.9 102.5 102.3 102.2 101 0 4 115.0 130.0 127.2 118.4111.7 109.8 111.4

82.5 98.8 102.2 102.0 1040 0 103.9 138.7 155.5 151.2 147.9 151.6 153.0

75 109.1 110 0 0 109.2 109 0 2 112.6 152.2 174.9 178.7 168.5 172.6

70 113.0 115.3 114.8 1~5.0 122.0 154.8 179.4 181.0 178.4 185.9

60 119.6 119.3 118.6 ll~e4 125.6 164.8 182.2 184.4 183.9 183.0

50 131.8 132.5 129.8 130.2 134.9 135.2 166.5 168.0 l/l7J7 169.0

l:I:J to 190 iii iii I j i I I I I j i 1 i L A 70 0k Mn /801 IIIIIII ...... J---__ IL r 7'"1' 60% Mn I I I ~~/~"'" -;V l 1701 IIIIII ~//....-- IA N75 % IMn Vj v VJ/~ l~ j50%IMn ~ III / 1\ 10 / 1/j/ Ii k I \ l '0 150 ;, VI ~ ...J.- ~82.51%Mn ~~ ~ /1 11 I III II U 140 // 1\ ~ ~ IV II \! ~ I~ I ~ III ! 11/ / ~ V"", \ o 120 ~ V / ...--/~ ~ ~ / /:J/' V V ~~ \ E110 "'-'-, ~ ..-'~. J./' [\"'""-- 1\ 90:tJ Mn £\00 [};7' \ \: 19Z% IMn I " ~ 90 1\ 9~ %MrJI i \ tf) 80 ~- Slow 300 -400 500 600 700 800 900 1000

C.ooled Temperature 0 C \.No FIGURE 4 -E:FfECT OF QUENCHING TEMPERATURES ON ELECTRICAL RESISTANCE OF COPPfR-MANGANE5E ALLOY~ • 31.

below 500oe.· Between 5000 e and 6000e all of the alloys show an abrupt increase in resistance which continues on up to a maximum and then drops off again as the temperature is increased. All of the alloys, except the 50% manganese alloy, reach a maximum resistance between 7000 e and 750oe. The 50% alloy does not reach it's maximum resistance until BOOoe. The 96% alloy, after reaching a maximum at 750oe, drops off sharply to a value considerably lower at 10400e than in the slow cooled state. The 90% and 92% manganese alloys after reaching a maximum at 7000e to 7500e drop off to a resistance at 9000e and 10000e nearly equal to that of the slow cooled alloys. The 82.5% alloy after reaching a maximum at 7000 e shows very little change in resistance with further thermal treatment. The alloys containing from 50% to 70% manganese after reaching a maximum at 7500 e decline slightly at 8000 e and B50oe. The 60% manganese alloy exhibits the greatest change of resistance of any of the alloys studied. It will be seen from Figure 4 that as the temper­ ature of quenching for the various alloys approaches the solidus the trend of the resistance gradually changes from sharply downward for the 96% alloy to 32.

upward for the 70% and 75% alloys and then reverses again to upward for the 50% alloy. Figure 5 shows the change of resistance, at various temperatures, with composition of the alloys. The results from the electrical resistance measurements of the alloys after various heat treat­ ments indicate that the 96% alloy manganese alloy is of a different nature thah the remainder. The 92% and 90% alloys are very similar, with the 82.5% alloy being intermediate between the high manganese alloys and the low manganese alloys. The alloys containing from 60% to 75% manganese behave very much alike as regards resistance and are probably of a similar nature. Below 60% manganese the alloys change some­ what as shown by the decrease in resistance. This change is probably due to the copper beginning to ex­ ert its influence on the alloys. A more detailed interpretation of the electrical resistance results will be given later in the discussion in conjunction with the other properties of the alloys. - A B I i'o- , 4''''':1: 180 III ...... --JC I "\.;sp~ I 180 / ~r-.~ ~\ 170 II I J II ~ II> .10 L--+- I f· \D, o It1 o 160 I II III I;C I \I cr>)( 160 (:t')'IC E E I U ~J ~ 150 III Ir I/II \ I ~150

~ (/)

C/) 140 II I II ,;. III II EJAlO E ~ 1 " ..!: o o iI ( _ 130 I\ tf f I I --+-~:A (]I 130 \ \I (11 u u c C \\ j E. 120 I ..\J If I ,IT J,/. 9" I .E 120 V") I,f) \ ~ I If") -if) a.. \ cr:: \1°1 \\\/1 I h L III & 110 \ \I \J _ 1':1 ~1 II Iii:.. tOO 90 80 TO bO 50 100 90 80 -ro QO 50

Weight 0!c> Manganese Weight % Mangqn~s(:l FIGURE 5- EFFECT OF MANGANESE CONTENT ON RE515TANCE OF COPPER-MANGANE5E ALLOY5 AT VARIOU5 TEMPERATURE5 '-.,J \.)J • 34.

Hardness

The hardness of the alloys after various thermal treatments is shown in Table IV. These experimental results are also shown graphically in Figure 6. Again the 96% manganese alloy is apparently different from the rest of the alloys studied. The slow cooled alloy after a light softening at 3000 e shows no change in hardness until 7500 e is reached. At this temperature the hardness increases from 110 0 Rockwell "BlI to 118 Rockwell liB". At 800 e the hard- ness declines to its original value and after a slight rise at 850°C, decreases sharply to 64 Rockwell IIBIl at a temperature near the solidus. The remainder of the alloys all show a break in hardness between 5000e and 6000C. The 92% and 90% alloys show a gradual increase in hardness from 5000 e to 7500 e, where they reach a maximum. As the temperature is increased they decline to a minimum at 8500 e, and then rise again to a constant hardness as the solidus is approached. The hardness of the 82.5% alloy remains constant up to 600°C. From 600°e to 8500 C the hardness declines Table IV

Hardness of Manganese-Copper ~~loys

Rockwell B Hardness

2 hours at

Slow 0 0 LLwm. Cooled 4000 5000 5500 600 700 7500 8000 8500 9000 10000 10400 96 117 110 110 110 III 110 118 III 110 116 75 64 92 72 72 74 80 86 88 94 80 66 82 80 90 '71 72 76 82 82 85 87 72 63 77 76 82.5 79 82 83 88 79 70 57 55 55 75 75 88 88 88 92 88 70 57 54 58 70 88 92 91 96 92 68 51 61 52 60 89 90 90 93 82 59 61 56 61 50 '79 80 81 83 70 59 60 58 61

c.N CJl A B ~

0/ ~t\ V~ 90 r1( 0..:---' 130 ~ l/ \ ~ 0 ~\---- 1>-5 / 0 Mn ~ ~\ } 120

~ y \ ~ 96% ../ ~ Mn .... 1/\ 80 , / \ liD - I/) ---- ([) 50 "10 Mn

Temperature 0 C FIGURE: 6 -[FFeCT OF QUENCHING TEMPERATURE ON HARDNESS OF MANGANESE-COPPER ALLOY5

\>l .0\ 37.

to a minimum and then rises sharply at 900oe. The alloys containing less than 82.5% manganese all show an increase in hardness at 5500 e where they attain their maximum hardness. On further heating the hardness decreases to a minimum at 750oe. The 75%, 60%, and 50% alloys increase in hardness as they near the solidus, but the 70% alloy increases rapidly between 7500 e and 800oe, and then drops abruptly again at 850oe. From the foregoing results it can be seen that the 96% alloy passes through a different mechanism as it is heated, than the rest of the alloys. The 92% and 90% alloys behave very similarly and may be considered to be of the same constitution. The 82.5% alloy is again intermediate between the high and low manganese alloys and possesses some of the properties of both. The alloys containing less than 82.5% manganese all undergo the same relative changes in hardness as they are heated. The only exception is the increase of the 70% alloy at 800oe, followed by a sharp decline on rurther heating. The 70% alloy shows the greatest change in hardness of all the alloys. Figure 7 shows the variation of hardness with composition of the alleys at ~arious temperatures. D A 110

100

II) ~ 90 ~ c: ." L ~ C 80 I .900OC rn \~ "V 70 (].I • ~ \ ~ 850C ~60 g ~ v....c -~ 8~ ~ cr ~ X ~ - 50 --- 100 90 90 70 60 50 Weight % Mangan~5~

~ B /10 \ "~ 100 \~ (f) ~ ~ ~~ ~ 90 ...... C ~ .../, lo~"'- "U ~~ ~ 0 ~ L V ~ ~ o 80 V / I ~7' ~Joo ...... , !D TO l "'- ...... ell \ ~ 50°<:' ~ ~ r---.. 1 ~ 60 u ~ ,/ 700°C o 0:: ~ 50 / 100 gO 80 70 60 50 Weight % Manganese FIGURE7- EFFECT OF MANGANESE CONTENT ON HARDNE55 OF MANGANESf>COPPER ALLOY5 AT VARIOUS TEMPERATURES. 39.

From the curves it can be seen that in the slow cooled state the hardness decreases from the highest manganese alloy down to the 90% alloy where it reaches a mini- mum. As the manganese content is further decreased the hardness rises again until the 60% alloy is reached. Further addition of copper causes the hard­ ness to decrease. This same general trend holds until 5500 C is reached where the change in hardness for the various alloys as previously shown. The significance of the changes in hardness of the alloys will be further discussed in relation to thedher properties of the alloys. 40.

Preparation of Specimens for Photomicrography

Polishing: -A i inch length was cut from each alloy and mounted in bakelite. The specimens were first polished wet on canvas laps using succeeding­ ly finer abrasives, and then finished on felt with levigated alumina. It was soon discovered, however, that the alloys had a very great tendency to pit during the polishing and were difficult to examine under the microscope. Wet polishing was then abandoned and the speci­ mens were polished by hand on emery paper, beginning with No. 2 and finishing with No. 0000 paper. They were then polished wet on felt using Fisher No. 2 alumina and finished on felt using Fisher No. 3 ­ ina at 550 revolutions per minute. By polishing dry through 0000 emery paper and then finishing wet, the amount of pitting was kept at a minimum. The tendency of the copper-manganese alloys to pit during wet polishing increases with manganese content. Etching:- After preliminary attempts to etch the polished specimens with the ordinary reagents, it was apparent that an investigation to determine good etching methods was necessary. The alloys containing greater than 75% manganese oxidize very rapidly where 41.

etched and the surface becomes completely obscured by a black film. After using seventy five reagents, only four were found that showed any promise of being useful for future work. They were dilute , citric acid, a solution of sUlphur dioxide, and a -potassium dichromate solution. Citric acid attacks the alloys vigorously leaVing many residual scratches. A 10% solution of sulphur dioxide etched the alloys very , but left the surface highly colored. Although the microstructure of alloys etched with citric acid or sulphur dioxide could be studied under the microscope, they did not photograph well and these reagents were discarded. A one percent solution of acetic acid was chosen as the etchant for the alloys containing greater than 75% manganese. Specimens etched with acetic acid were covered with a thin trans­ parent film of oxide which in no way interfered with the micro-examination or photographing of the alloys. Acetic acid would not etch alloys containing less than 75% manganese, and the potassium dichromate-sulphuric acid solution was used for the alloys between 50 and 75% manganese. The solution used contained 2 grams of potassium diohromate, 8 cc of sulfuric acid (sp.gr.l.84) and 100 cc water. One drop of Hel was added to 25cc of the solution just before using. When the alloys were etched with the dichromate solution, the surface of the specimen was left with a coppery appearance. The etching times for the various alloys was found to be very critical and unless the proper time was used, it was necessary to repolish and re-etch. When acetic acid is used to etch the high manganese alloys, a highly colored film first appears, and if the etching is stopped at this point, the microstructure is badly obscured. If the etching is allowed to pro­ ceed until this colored film just disappears, the microstructure is clearly visible. If the etching proceeds much beyond the point where the colored film disappears, the surface becomes covered with a black oxide which again obscures the miorostructure. The time of etching the high manganese alloys with acetic acid is best determined by observing the change of colors upon the surface during the progress of the etching, and stopping the action at the point where the surface appears to be black to the eye. The time of etching the lower manganese alloys with dichromate is not as critical as when etching the high manganese alloys with acetic acid. A black film will sometimes appear on the surface of the speci­ men when the attack begins, but upon further etching this film disappears leaving a coppery surface. The time of etching with dichromate decreased with increasing manganese content. If the alloys are etched too long, however, the coppery film becomes ,spotted with areas that are not transparent. Etching with dichromate also frequently proceeds unevenly over the surface and it is advisable to agitate the specimen vigorously in the reagent to dislodge gas bubbles that form. The 50% manganese alloy does not etch readily with-dichromate unless rubbed with cotton during the etching. The surface apparently becomes passive when the film is first formed. The 50% alloy is the only one, however, that can be rubbed with cotton because the film on the other alloys becomes scratched with rubbing. The alloys exhibit a great tendency to leaving residual scratches in relief when they are etched. These scratches cannot be removed by the usual method of repolishing and etching, because once the oxide film is formed on the surface of the alloy by etching ­ it cannot be replished. This oxide film is apparent­ ly very hard, and if an attempt is made to repolish the specimen on the felt lap to remove residual 44.

scratches, the surface becomes even more scratched. If the specimen is etched improperly or shows too many residual scratches, it must be repolished through the entire series of emery paper and felt laps. In order to keep the residual scratches at a minimum, the specimen should be polished as quickly as possi­ ble on the felt laps, and with little pressure. All of the high manganese alloys that were ex­ amined and photographed, and reproduced here were polished as described above and etched with one per­ cent acetic acid. The alloys containing less than seventy five percent manganese were etched with the potassium dichromate solution. 45.

Microstructure

Figures 8 and 9 show the microstructure of the alloys after various thermal treatments, and examination of these photographs will reveal several marked diff­ erences in the alloys. The 96% manganese alloy, when slow cooled, consists of two phases of approximately equal amounts. As the alloy is heated at increasing temperatures for two hours and quenched there is little or no change in the structure until l0400 C is reached. At this point one phase goes into solution leaving a twinned structure which is the gamma solid solution. The alloys containing from 70% to 92% manganese all have the same structure in the slow cooled state. They consist of a network structure' with only a relatively small amount of second phase in the grain bounderies. Since the amount of second phase in the grain bounderies is the same in all of the alloys, it seems logical to assume that this phase cannot be the same in all of the alloys because the volume of the boundery material does not change with drecreasing amounts of manganese. The alloys do differ, however, as they are heated to higher temperatures. The temperature necessary to dissolve the network phase 46 •

•

t 47_

o o· o ...... 0

o o 0­ (;) .. o 10

• 48.

is lower with decreasing manganese. The 92%, 90% and 82.5% manganese alloys are twinned solid solutions when quenched near the solidus indicating that they are also the gamma solid solution. The 70% and 75% alloys when quenched from 8500 C are a single phase, but show evidences of veining and are not twinned. They are a different solid solution than that found in the higher manganese alloys. The slow cooled alloys of 60% and 50% manganese differ from the higher manganese alloys in that they are one phase. They do, however, show a two phase network structure when quenched from 600oc, indicat­ ing that they must pass through a narrow two phase area at this point. The network disappears at 700°C and when the alloys are quenched from 850°C they are a single solid solution. Veining persists in the 60% alloy causing a -like structure in the grains. The 50% alloy does not show veining. The twinning of the slow cooled 50% alloy is due to the influence of the copper on the alloys beginning to become prominent.

Although not enough alloys were stud~ed to attempt to determine an eqUilibrium diagram of the copper-manganese system, the alloys as shown here differ in several respects from any previously pUblished diagram. The principal differences between previous diagrams and the results reported here are:

1. According to Ishiwara's work, all of the alloys should consist of two phases at temperatures below o 900 e, but as shown in Figures 8 and 9 the alloys from 50% to 75% manganese are single phase above 800oe, as well as the 50% and 60% alloys being single phase at all other temperatures except 600oe. The results of Perrson are more nearly in agreement since they predict a one-phase structure above 7000 e for alloys from 50% to 82.5% manganese. His diagram, however, shows two phases for the 50% and 60% alloys when slow cooled. 2. All previous diagrams show alloys from 50% to nearly 100% manganese to consist of the same two phases. From the author's results this is not possible. The 96% alloy is definitely different from the remainder of the alloys studied, and since the second phase in the grain bounderies of the other alloys occupies near­ ly the same volume in all cases, it does.not seem like­ ly that they are composed of the same entities. 50.

Discussion of Results

In order to compare the results of hardness and electrical resistance of the alloys after various heat treatments, the data was plotted separately as shown in Figures 10 and 11. It can be seen from these curves that the alloys containing from 50% to 82.5% manganese behave similar­ ly as regards hardness and resistance. They all show an abrupt increase in resistance and a decrease in hardness at 600°C. The only explanation that can be logically offered for this behavior is to consider the slow cooled alloys to be in a completely ordered state and, upon reheating to 600oC, to break down to a randomly oriented solid solution. Since there is no detectable change in the miorostructure of the alloys at this temperature, this is further evidenoe that the system must be one containing an order­ disorder transformation. The increase in resistance of the 90% and 92% alloys at 6000 indicates that they also undergo dis­ ordering while the increase in hardness at this temperature seems to indicate that the alloys also decompose upon reheating. The decomposition tends to lower the resistance accounting for the fact that the 51.

c.D I <:;) to l( aI ~E ~ A l..J 92.% Mn B ~ITO ~""'''oW--~--...... --....., 110 ~ ~'40 I----+---+---+-----t 100 (f) ~ ~ L 0 ~ c ~ ~ 90~ E'50 100 ""'2 !'30 ..s:::; 0 o l. o ~ 0 ~30 goI ~'lO 80I ~ o en t; !D ~ 110 80 lr') 110 70= ! . =~ ~. i:Y U. ~q~\ '> ex:: $ U :> --100 60-X ~90 7O-:} ~ U ~ U 0 Lf0 ~ C( (/') TO 60 Cr>90 50 Slow 500 rOO 900 1100 Slow 400 600 600 1000 CooleJ 0 CoolQCJ . TQmperature C T~mp(2rotur~ °C

c.D IQ <"'1)<, 90% Mn C E 82.5 %Mn D ~ u ~ 100 ~ ~90 ~--+-~l...t---+-----t 90 ~ C If) C

00 ~ ~170 80""E I 0 ~g,t?r ~ ~IZO ~'50 I---+-~I-+-""""~+---f 70 c: (' eocQ c CO:r: E. ~() E ~ "" _..... ~ V') 'iii /10 VI 70 ~ 'iii 130 I----+-__-++-~r_+_+_~60 ~ ~ ~ ~ ~ ~fl~\~ u~cl u u u ~ ~.'_-,OO ''\9 N 0 C 110 50 U u 60rY: '0 o ~ ~ ~ en 90 !50 (f) 90 40 Slow 400 600 800 1000 Slow 400 600 800 1000 Coo/e'd Coole4 Temperature °c T~mperatur~ °c FIGURE 10- EFFECT OF QUENCHING TEMPERATURE ON HARDNES5 AND RESI5TANCC OF COPPER ­ MANGANESE ALLOYS \P I lQ o 'g >( "1 E 75% Mn A ~.. 70% Mn B u £ 100 (.)200 to zoo \.. IOO(J) QI (f) ~ ~ e<;'i? (f) rv-~sp ~ ~ 0... ~ ~o<" ~ ~6vd C '" 90 t:

.g Io .. 60% Mn C 50% Mn 0 "'E () 200 100 l [.. f/l ()e~ ""'- r> C/) Hor 8 ~ E ;8'.. 90~ ""0 <5 l \Vt o 't\o~ \c:;' ,1 80 I ~ ~CO III 0 70~ (fz ~5i' ftQ(l~ ~~0 :t­ o u ~l/.~\ P ; o - ~ (i: 0 o r> A 60~ () 12 ~ l c;: 120 .,. V <» "\3 0... ('t 'v Q.. cf) 100 50 C{) 100 50 Slow 400 000 800 Slow <400 600 800 T~mperature Cooled Cool.1i 0 C Temperature °c FI GURE II - EFFECT OF QUENCHING TEMPERATURE ON HARDNE58 AND RE51~TANCE OF COPPER­ MANGANESE ALLOY5 53.

net resistance change of these alloys is less than for the other alloys. The 96% alloy decomposes upon slow cooling as is evident from the microstructure. The increase in resistance at 7500 C may be due to a transformetion from alpha to beta manganese. The qualitative results obtained for the vibration damping capacity indicates that all of the alloys ex­ hibit a higher damping capacity in the ordered state than in the disordered condition. Although there have been many objectors to considering this system one of ordering, this explana­ tion is the only one that can fully account for the present results. 54.

A study of the copper-manganese system was made upon alloys c.ontaining from 50% to 965& manganese after various heat treatments. Values for hardness, electrical resistance, and coefficient of expansion were reported. and many of them differ markedly from previous results beaause of the purity of the manganese used in making the alloys and the carefUl control of heat treatment. A qualitative study of the vibration da.mping capacity was also made. The microstructure of the alloys was studied and many photOlnicrographs were reproduced. Although no attempt was made to present an equilibrium diagram, the essential divergencies of res'a1ts found in this investigation from thoBe of earlier workers were pointed out. Although more accurate conclusions could have been drawn if' more alloys had been available for study, the author feels that these experimental results presented here are of a definite value 1n shedding further light u.pon the present knowledge of eopper­ manganese allQYs. It 1s felt that more work must be done before the eonstitution diagram (fan be certainly established. 55.

Acknowledgment

The author wishes to thank the Missouri School of Mines & Metallurgy for providing the opportunity and facilities for carrying on this investigation, and Professor C. Y. Clayton of the Metallurgical Engineering Depart­ ment and Mr. S. M. Shelton of the U. S. Bureau of Mines for invaluable advice rendered during the progress of the work. 56.

Bibliography

1. Lewis, A. E., Alloys of Manganese and Copper: Jour. Soc. Chern. Ind., Vol. 21, 1902, pp. 842-844 2. Wologdine, S., Alloys of Manganese and Copper: Rev. Metallurg., Vol. 4, 1907, pp. 25-38. 3. Sahmen, R., Alloys of Copper with Cobalt, Iron, Manganese and : Zeit. anorg. Chemie, Vol. 57, 1908, pp. 1 - 33. 4. Zemczuzny, S. F., Urasow, G., and Rykowskow, A., Alloys of Manganese with Copper and Nickel: Zeit. Anorg. Chemie, Vol. 57, 1908, pp. 253-261. 5. Bain, E. C., Crystal Structures of Solid Solutions: Trans. A.I.M.E., Vol. 63, 1923, pp. 625. 6. Patterson, R., Crystal Structure of Copper­ Manganese Alloys: Phys. Rev., Vol. 23, 1924, p. 552. 7. Corson, M. G., Manganese in Non-Ferrous Alloys: Trans. A.I.M.E., lnst. Metals Div., Vol. 78, 1928, p. 483. 8. Smith, C. S., Alpha Phase Boundry of the Ternary System, Copper-Silicon-Manganese: Trans. A.I.M.E., Inst. Metals Div., Vol. 89, 1930, p. 164. 9. lshiwara, T., Equilibrium Diagrams of the Aluminum-Manganese, Copper-Manganese, and Iron­ Manganese Systems: World Eng. Congr., 1929, Paper No. 223. 10. Ishwara, T., On the Equilibrium Diagrams of the Aluminum-Manganese, Copper-Manganese and Iron­ Manganese Systems: Tohoku Imp. Univ., Sci. Rep'ts., 1930, Sere 1, Vol. 19, p. 499.

~ 11. Persson, E., and Ohman, E., A High Temperature Modification of Manganese: Nature, Vol. 124, 1929, p. 333. 57.

12. Sekito, S., z. KTistallographie, Vol. 72, 1929, p. 406. 13. Persson, E., X-Ray Analysis of the Copper-Manganese Alloys: Z. Physik. Chern., Abt. B., Vol. 9, 1932, p. 25. 14. Valentiner, S., and Becker, G., Susceptibility and Electrical Conductivity of Copper-Manganese Alloys: Z. Physik, Vol. 80, 1933, p. 735. 15. Smith, C. S., Metals Handbook, 1939, p. 1350. 16. Broniewski, W., and Jas1an, S., Alloys of Copper with Manganese: Ann. Acad. Sci. Tech. Varsovie, Vol. 3, 1936, p. 141. 17. Hunter, M. A., and Sebast, F. M., The Electrical Properties of Some High Resistance Alloys: J. Am. Inst. Metals, Vol. 11, 1917-18, p. 115. 18. Korenov, N. I., Alloys of Manganese with Copper: Am. secteur, Anal. phys. chern., Inst. Chern. Gen. (U.S.S.R.), Vol. 11, 1938, p. 47. 19. Dean, R. S., Anderson, C. T., Moss, C., and Ambrose, P. M., U. S. Bureau of Mines, R. I. 3477, November 1939. 20. Krings, W., and Ostmann, W., The Ternary System Copper-MAnganese-Aluminum and it's Magnetic Properties: Ztschr. anorg. a11gem. Chern., Vol. 163, 1927, p. 145.

21. Ki~o11, W., Hot Workable Manganese and it's Ductile Alloys: ztschr. Metall., Vol. 31, (II), Jan. 1939, p. 20. 58.

INDEX

Page Acknowledgment ...... 55 Alloys Composition ...... 17 Preparation ...... 16 Bibliography ...... 56 Cold Work, Effect of ...... 21 On Hardness •••.•••.••••••••.•• 21 On Resistance ••••..••••••.••• 21 Contents, Table of ...... I Discussion of Results ...... 50 Electrical Resistance ...... 28 Method of Measuring ••••••••••• 28 Results •••••••••.•••.•.• 29,30,33,51,52 Expansion, Coefficient of ...... 23 Hardness ...... 34 Results •••••••••••••••••• 35,36,38,51,52 Heat Treatment ...... 18 In Air ...... 18 In Vacuum ...... l8 In Helium ...... 19 Historical •...... 3 Constitution ••••••••••••••.••• 3 Electrical Resistance ••••••••• 11 Expansion, Coefficient of ••••• 13 Hardness ...... • 15 Mechanical Properties ••••••••• 13 59.

INDEX (continued)

Page Illustrations, List of •••••••••••• II Introduction ••.•...•...... ••...••• 1 Microstructure ...... 45 Photomicrographs ...... 46, 47 Photomicrography, Preparation of Specimens for ••••••••••••••••••••• 40 Etching ...... 40 Polishing ...... 40 Summary •••...... •..•...•....•..• 54 Vibration Damping Capacity...... 26