Tensile and Fracture Toughness Behavior of Waspaloy. Martin J

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1-1-1983 Tensile and fracture toughness behavior of Waspaloy. Martin J. Sippel

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Recommended Citation Sippel, Martin J., "Tensile and fracture toughness behavior of Waspaloy." (1983). Theses and Dissertations. Paper 1932.

This Thesis is brought to you for free and open access by Lehigh Preserve. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of Lehigh Preserve. For more information, please contact [email protected]. TENSILE AND FRACTURE TOUGHNESS

BEHAVIOR OF WASPALOY

by Martin J. Sippel

A Thesis Presented to the Graduate Committee of Lehigh University in Candidacy for the Degree of Master in Science in Metallurgy and Materials Science

Lehigh University 1983 ProQuest Number: EP76205

INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted.

In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest

ProQuest EP76205

Published by ProQuest LLC (2015). Copyright of the Dissertation is held by the Author.

ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 CERTIFICATE OF APPROVAL This thesis is accepted and approved in partial fulfillment of the requirements for the degree of Master of Science.

DATE) '

Professor in Charge

Chairman of the Department of Metallurgy and Materials Science

n ACKNOWLEDGEMENTS

The author wishes to thank the Ingersoll-Rand Company and Mr. J. A. Larson, Manager of the Ingersoll-Rand Central Materials Service Laboratory for providing the materials and facilities necessary to perform this investigation.

Mr. T. J. Coates, the author's immediate supervisor, deserves special recognition for his support, guidance and understanding throughout the course of this program.

Appreciation is extended to the author's thesis advisor Dr. A. W. Pense for his comments and useful suggestions during the course of this project.

Appreciation is also extended to Mr. D. R. Bush for his expert assistance with the electron microscopy and to Mrs. S. Price for her typing prowess.

Finally, the author wishes to deeply thank his loving wife, Barbara, for her continual understanding, encouragement, devotion, and endless patience, not only through this project but throughout the author's lengthy graduate program.

m TABLE OF CONTENTS

Page

Abstract 1

I Introduction 3

II Testing Procedure 5

III Results 10

IV Discussion of Results 13

V Conclusions 17

Tables 19

Figures 22

References 36

Vita 38

IV ABSTRACT The tensile and J,- fracture toughness behavior of a large Waspaloy forging was characterized as a function of temperature from 73°F (23°C) to 1400°F (760°C). The tensile and yield strengths exhibited gradual decreases with increasing test temperature to 1200°F (649°C), while the ductilities exhibited gradual decreases to 1000°F (538°C). Above 1200°F (649°C) the tensile strengths decreased rapidly and the ductilities increased gradually. Examination of these tensile fractures revealed that the cracking at all of the test temperatures occurred as microvoid coalescence with a minor amount of intergranular decohesion. The abrupt change in tensile behavior above 1200°F (649°C) was postulated to be caused by enhanced dislocation motion as a result of thermal activation.

The JJC fracture toughness of the Waspaloy forging exhibited a gradual decrease with increasing testing temperature to 1000°F (538°C). Examination of these specimens revealed that these fractures were dominated by transgranular facets with relatively few microvoids. This fracture morphology indicated that planar slip was the predominant mode of deformation in the temperature range of 73°F (23°C) to 1000°F (538°C). The J,„ samples tested at above 1000°F (538°C) exhibited dramatic reductions in the fracture toughness, reaching a minimum value at 1400°F (760°C). Examination of these fractures revealed that the cracking was dominated by intergranular decohesion. The major reduction in the fracture toughness between 1000°F (538°C) and 1400°F (760°C) was attributed to the transgranular to intergranular fracture mode transition which occurred in that temperature regime. -1- The tensile behavior of the Waspaloy forging did not directly correlate with the observed fracture toughness response. In addition, differing fracture mechanisms were operative during the two phases of testing. It was concluded that the differing amounts of triaxial stress during the tensile and fracture toughness tests resulted in differing fracture mechanisms and significantly influenced the overall mechanical response of the alloy.

-2- INTRODUCTION Waspaloy is a gamma prime strengthened nickel-base superalloy which has been extensively utilized by the aerospace and industrial gas turbine industries since its development in the late 1940's. Typically used as a forged product, this material exhibits an outstanding balance of mechanical properties which makes it attractive as a turbine disc and blade alloy. Waspaloy possesses excellent tensile and creep properties in addition to substantial corrosion and oxidation resistance at elevated temperatures. Another important characteristic is the good forgeability of the alloy. Waspaloy has been successfully forged into large turbine discs in excess of 50 inches (127 cm) in diameter and over 3500 lbs. (1588 kg) in mass. Design and life analysis of modern rotating components requires a detailed knowledge of numerous material behavior parameters at ambient and elevated temperatures. These material behavior parameters change with differing processing techniques, heat treatments and size of components and, unfortunately, these changes often lead to substantial reductions in critical properties. A limited amount of work has been published in the literature concerning the fracture toughness behavior of nickel-based superalloys with respect to temperature. Room temperature data for Inconel 718

(1), (2), (3), (4)t IN_738 (5), (6)) Rene 41 (7)j and Incone1 706 (8) -s available from various sources. Recently, Mills has published fracture toughness results on Inconel X-750 at several temperatures to 1200°F

(649°c) (9)- No published data could be found concerning the tensile and fracture toughness behavior of large superalloy forgings. Consequently, this study was undertaken to evaluate the tensile and fracture toughness behavior of a large Waspaloy forging at several temperatures.

-4- TESTING PROCEDURE Materials The Waspaloy forging evaluated in this study was produced to Aerospace Material Specification (AMS) 5707E. The initial ingot was vacuum induction melted, vacuum arc remelted, and converted into an 18 inch (45.7 cm) diameter forging billet. This billet was subsequently closed die forged into a disc configuration 48 inches (122 cm) in diameter and having a mass of 1700 pounds (771 kg). The chemical composition of this Waspaloy forging, presented in Table 1, shows the analysis to be well within the specification ranges. In accordance with AMS 5707E, the forging was given the following heat treatment. Solution treated at 1850°F (1010°C) for 4 hours and oil quenched. Stabilized at 1500°F (843°C) for 4 hours and air cooled. Aged at 1400°F (760°C) for 16 hours and air cooled. The solution treatment temperature was deliberately low in order to retain some of the coarse gamma prime and carbides which formed during the sub-solvus forging operation. These coarse precipitates were not solutioned so that some of the strain energy from forging was retained in the structure. Subsequent double aging of the partially solution treated material resulted in the precipitation of gamma prime in two additional sizes. A typical example of the microstructure is shown in figure 1. The largest gamma prime particles were retained from forging, the intermediate size particles were due to the stabilization aging at 1550°F (843°C) and the fine gamma prime particles were formed during the -5- 1400°F (760°C) aging treatment. The majority of the carbide precipitates in the microstructure were along the grain boundaries and were the M23 Cg variety. Large blocky carbides were occasionally found within the grains and these were the MC variety * '. Tensile specimens were prepared from around the periphery of the forging in a radial orientation from the approximate mid-thickness position. Compact tension samples, 1.00 inch (2.54 cm) thick, were prepared from around the periphery of the forging from the approximate mid-thickness position, such that the crack planes were in a chordal orientation. Tensile Testing Standard 0.250 inch (.635 cm) diameter threaded tensile specimens were tested at 73°F (23°C), 800°F (427°C), 1000°F (538°C), 1200°F (649°C) and 1400°F (760°C) using a closed loop servohydraulic testing machine. All of the tensile tests were performed in ram displacement control at a rate of 0.005/min. During each tensile test, the sample temperature was controlled to within ±5°F (±3°C) of the desired testing temperature using a three zone resistance furnace with independent zone controls mounted on the load frame. The ultimate tensile strength for each sample was determined using the maximum load recorded and the initial cross-sectional area of the gage. The yield strength for each sample was determined using the 0.2% offset method in ASTM E8. The percent of elongation and reduction of area were determined at room temperature by fitting the fractured halves of the specimens together and measuring the final gage length and minimum diameter. -6- Fracture Toughness Testing

JTr fracture toughness tests were conducted at 73°F (23°C), 800°F (427°C), 1000°F (538°C), 1200°F (649°C), and 1400°F (760°C). The single specimen method was used and the testing followed the guidelines set forth in ASTM E813. Each specimen was precracked at ambient temperature to an a/w of 0.57 using a maximum stress intensity of 30.0 ksi sfTn. (33.0 MPasfm" )• Testing was conducted on a closed loop servohydraulic machine using ram displacement control, and the unloading compliance of each specimen was used to monitor the crack advance. During each test, the specimen temperature was continuously monitored and controlled to within ±3°F (±2°C) of the desired temperature. This was accomplished by using a large cylindrical resistance furnace mounted between the columns of the load frame. The load-line displacements of the specimens were measured using an apparatus which translated the displacements outside of the furnace where they were continuously monitored using a high sensitivity extensometer. Throughout each test, the load versus the load-line displacement of the sample was documented on an X-Y recorder, and a record for a typical sample tested at 1200°F (649°C) is shown in figure 2. Severe frictional problems at elevated temperatures between the devices, pins, and sample were overcome by coating all of the contacting surfaces with silver and collodial graphite.

•7- The value of J for the individual unloadings for all of the specimens was determined from the load versus load-line displacement curve using the following equation:

j = A (f(aQ/W)) Bb where: A = Area under load, load-point displacement record in energy units, B = specimen thickness, b = uncracked ligament, W - a., W = specimen width, a = original crack size, including fatigue precrack,

2 f(aQ/W) = 2 (1 +<*)/( l +°< )

2 <* = ((2a0b) + 2(2a0/b)+2P - ((2a0/b)+l)

2aQ/b = 2 aQ/b = 2aQ/(W - aQ) For each specimen, an R-curve was constructed by plotting values of J as a function of the change in crack length (a). The value of JjC was then calculated as the value of J at the intersection of the least squares regression line through the crack extension data and the blunting line defined by the equation:

J =Aa (YS + UTS)/2 where: A a = change in the total crack length YS = 0.2% offset yield strength UTS = ultimate tensile strength

Each specimen met all of the validity criteria specified in ASTM E813. Electron and Optical Microscopy Representative tensile and compact tension specimens, which were tested at the various temperatures, were sectioned and gold coated for electron microscopy. Each fracture was examined in a scanning electron microscope to characterize the fracture mechanism at the respective testing temperatures. The SEM was operated at an accele- rating potential of 20 KV, and the samples were at a working distance of 1.3 cm at a tilt angle of 30°. All of the examinations were performed using secondary electrons. Two representative samples of the Waspaloy forging were sectioned, mounted, mechanically polished, and etched to examine the microstructure. One sample was etched in Marble's Reagent in prepa- ration for optical microscopy. This sample was examined with a light metallograph to observe the structure to a magnification of 800x.. The second sample was electrolytically polished using the etchant and procedure described in ASTM E407, #107. This sample was examined in an SEM to observe the microstructure to a magnification of 10,000x.

-9- PRESENTATION OF RESULTS Tensile Results The results of the tensile tests on the Waspaloy forging at 73°F (23°C), 800°F (427°C), 1000°F (538°C), 1200°F (649°C), and 1400°F (760°C), are listed in Table 2. This data is presented graphically in figures 3 and 4. The tensile and yield strengths were found to be relatively insensitive to testing temperature up to 1200°F (649°C). Figure 3 shows an approximately linear relationship between strength and temperature in this regime. Above 1200°F (649°C) the tensile and yield strengths were reduced significantly, reaching minimum values at 1400°F (760°C). The percent elongation and reduction of area values exhibited slight reductions with increasing test temperature up to 1000°F (538°C). Again, the ductility reductions were approximately linear as a function of temperature as shown in figure 4. Above 1000°F (538°C), the values of elongation and reduction of area increased significantly to maximum values at 1400°F (760°C). Fracture Toughness Results The results of the J integral fracture toughness tests on the Waspaloy forgings at 73°F (23°C), 800°F (427°C), 1000°F (538°C), 1200°F (649°C), and 1400°F (760°C) are listed in Table 3. These results are plotted as JIC versus temperature and KIC versus temperature in figures 5 and 6. The samples tested at 73°F (23°C), 800°F (427°C), and 1000°F (538°C), revealed that the fracture toughness of the superalloy decreased slightly with increasing temperature, but the values were in excess of -10- 430 in-lbs/in (75 kJ/m2). However, the samples tested at 1200°F (649°C) and 1400°F (760°C) exhibited dramatically lower toughness values which were less than 112 in-lbs/in (20 kJ/m ). This represents a factor of 4 reduction in the fracture toughness over a temperature range of 200°F

(111°C). Typical fracture toughness data for five individual' Waspaloy specimens at each of the testing temperatures are presented in figure 7 as a composite R-curve. This composite curve shows the reduction in the value of JIC from a maximum of 73°F (23°C) to a minimum at 1400°F (760°C). In addition, the slope of the (J) versus (Aa) regression line decreased markedly with increasing temperature, representing less ductile material behavior with increasing test temperature. Microscopy Results Scanning electron microscopy of the fractures of the tensile specimens which were tested at 73°F (23°C), 800°F (427°C), 1000°F (538°C), and 1200°F (649°C), revealed that the predominant fracture mode was microvoid coalescence with a relatively constant amount of intergranular decohesion. A region representative of these fractures is presented in figure 8, showing relatively large equiaxed microvoids but prominent intergranular features. The tensile sample which was tested at 1400°F (760°C) exhibited a fracture which was considerably more intergranular than the other samples, but extensive microvoid coalescence was evident. Figure 9 shows a typical region of this fracture which exhibits microvoid coalescence and intergranular rupture with microvoids on the grain facets. -11- Scanning electron microscopy of the fractures of the compact tension samples which were tested at 73°F (23°C), 800°F (427°C), and 1000°F (538°C), revealed fracture surfaces which were primarily faceted with small amounts of microvoids. Figures 10, 11, and 12 present typical regions of these fractures showing increasing amounts of transgranular faceting with increasing testing temperature. The compact tension samples which were tested at 1200°F (649°C) and 1400°F (760°C) exhibited fractures which were predominantly intergranular. Figures 13 and 14 present typical regions of these fractures. Intergranular decohesion and irregular microvoids on some isolated grain facets were visible on the fracture formed at 1200°F (649°C), but only intergranular decohesion was observed on the fracture formed at 1400°F (760°C).

•12- DISCUSSION OF RESULTS The mechanical properties of the Waspaloy forging exhibited a dual response as a function of testing temperature. Results of the tensile tests showed the alloy to be relatively insensitive to temperature to 1200°F (649°C), however, the fracture toughness results showed the alloy to be temperature sensitive in the range of 1000°F - 1200°F

(538°C - 649°C). The tensile and yield strengths of the forging were somewhat reduced as a function of temperature up to 1200°F (649°C). Above that temperature, the strengths were reduced dramatically. The elongation and reduction of area values exhibited gradual decreases to 1000°F (538°C) and above 1000°C (538°C) they exhibited significant increases. These results show the same basic trends as the Waspaloy data in Mil- Handbook V ^ ' indicate, although the absolute values of the results from the sample forging are significantly greater. Also, Mills has reported analagous tensile behavior as a function of temperature for (12) Inconel X-750 v ' which is a gamma prime strengthened nickel base superalloy similar to Waspaloy. Examination of the tensile fractures revealed that below 1200°F (649°C), microvoid coalescence was the predominant fracture mechanism. At 1400°F (760°C), microvoid coalescence remained the predominant fracture mechanism although a substantial amount of intergranular dimple rupture occurred. A significant reduction in the tensile strength/yield strength ratio, as observed for the 1200°F (649°C) and 1400°F (760°C) samples, typically is associated with sharply reduced ductility values and often -13- a fracture mode transition. However, the tensile samples tested at these temperatures exhibited increased ductilities and the fractures revealed copious amounts of microvoids. It is postulated that the materials decreased strength and increased ductility in the 1400°F (760°C) temperature regime resulted from increased dislocation mobility. The dislocation mobility was thermally activated by the higher temperature causing a reduction in the ability of the material to strain harden.

The JIC fracture toughness of the Waspaloy forging slightly decreased as a function of temperature from ambient to 1000°F (534°C). Above 1000 F (534°C), the fracture toughness dramatically decreased to a minimum value at 1400°F (760°C). This reduction in fracture toughness did not parallel the tensile behavior of the alloy. Comparing figures

3, 4, and 5 it can be observed that the JIC fracture toughness was substantially reduced in the temperature range of 1000°F - 1200°F (534°C - 649°C), while in this temperature range, the tensile and yield strengths exhibited merely a nominal decrease. In addition, the tensile ductility nominally increased between 1000°F (538°C) and 1200°F (649°C). Only above 1200°F (649°C) do the tensile properties exhibit any major deviations.

The examination of the fracture surfaces from the JjC samples revealed that at 73 F (23°C), the fractures occurred by transgranular cracking which formed facets and microvoids. These facets have been

13 14 observed in other nickel-base superalloys ^ '' t ;, \^) anc) generally result from operative planar slip mechanisms where intense dislocations motion is confined to a narrow band of crystallographic planes. The gamma -14- prime precipitates within these bands are sheared by the dislocations and then provide a weakened zone for additional slip. The 800°F (427°C) and 1000°F (538°C) samples exhibited similar fractures with increasingly pronounced facets. This indicates that planar slip within the material became progressively easier as the temperature increased. Consequently, the alloy's enhanced propensity for planar slip was responsible for the general decrease in the JJC fracture toughness response in the temperature range of 73°F (23°C) to 1000°F (538°C). The fractures of the samples tested at 1200°F (649°C) and 1400°F (760°C) exhibited predominantly intergranular decohesion indicating that a fracture mode transition occurred between 1000°F (538°C) and 1200°F (649°C). This ductile to brittle fracture mode transition was responsible for the material's dramatic reduction in J,c fracture toughness response in the temperature range of 1000°F (538°C) to 1400°F (760°C). Examining the overall mechanical response of the Waspaloy forging, it is important to note that in the temperature regime of 73°F (23°C) to 1000°F (538°C) the tensile samples fractured primarily by the coalescence of microvoids while the J,c samples fractured primarily by facet formation. Similarily, the tensile samples tested at 1200°F (649°C) and 1400°F (760°C) fractured primarily by widespread microvoid coalescence, but the J,- samples fractured primarily by intergranular decohesion. ASTM E399 defines the plane strain condition as:

2 B = 2.5 (KIC /CTYS) -15- where: B = specimen thickness

KTr = plane strain fracture toughness YS = 0.2% offset yield strength. For Waspaloy at 73°F (23°C) to 1000°F (538°C), the minimum specified thickness (B) necessary for plane strain conditions, is approximately 2.0 inches (5.08 cm). Therefore, neither the tensile samples nor the fracture toughness samples met the criteria for plane strain conditions. The plane stress plastic zone size may be approxi- mated by the relationship: 2

2 2~ 0-YS where: r = plastic zone diameter

KjC = plane strain fracture toughness

0"YS = 0.2% offset yield strength. For Waspaloy from 73°F (23°C) to 1000°F (538°C), the size of the plastic zone was approximately 0.15 inches (0.38 cm). This indicates that the plastic zone size within the tensile specimen was large with respect to the specimen diameter, while the relation of plastic zone size to the compact tension specimen thickness was small. Therefore it is postulated that the great difference in the degree of triaxial stress between the tensile samples and the fracture toughness was responsible for producing the two differing fracture mechanisms, microvoid coalescence versus faceting, which were observed on the various samples. -16- CONCLUSIONS This investigation has characterized the tensile and J,- fracture toughness behavior of a large Waspaloy forging as a function of temperature from 73°F (23°C) to 1400°F (760°C). The conclusions of this work are summarized as follows: 1. The tensile and yield strengths of the Waspaloy forging gradually decreased as a function of increasing testing temperature up to 1200°F (649°C). Above 1200°F (649°C) the strengths decreased rapidly to a minimum observed value at 1400°F (760°C). 2. The tensile ductility of the material gradually decreased with increasing testing temperature from 73°F (23°C) to 1000°F (538°C). Above 1000°F (538°C), the tensile ductilities increased gradually to the maximum value observed at 1400°F (760°C).

3. Examination of the tensile fractures of the Waspaloy specimens from each of the testing temperatures revealed that cracking occurred by transgranular microvoid coalescence.

4. Observed major reductions in the tensile and yield strengths above 1200°F (649°C) were postulated to be the result of enhanced dislocation motion caused by thermal activation which reduced the strain hardening capacity of the alloy.

5. The JjC fracture toughness of the Waspaloy forging decreased gradually as a function of increasing testing temperature from 73°F (23°C) to 1000°F (538°C). Above 1000°F (538°C), the fracture toughness dramatically decreased to a minimum observed value at 1400°F (760°C). 6. Examination of the compact tension fractures revealed that the -17- cracking of the Waspaloy in the temperature range of 73°F (23°C) to 1000°F (538°C), occurred predominantly by transgranular faceting. Above 1000°F (538°C) the cracking predominantly occurred by intergranular decohesion. 7. The gradual reduction of the Jr- fracture toughness from 73°C (23°F) to 1000°C (538°C) was attributed to enhanced planar slip as the testing temperature progressively increased. The major reduction of the JIC fracture toughness which occurred above 1000°F (538°C), was attributed to a transgranular to intergranular fracture mode transition. 8. Examination of the tensile and fracture toughness fractures revealed that different fracture mechanisms were operative depending on the type of test. This behavior was attributed to the degree of triaxial stress experienced by the samples, ie., the fracture toughness samples experienced a much greater triaxial stress than did the tensile specimens.

-18- TABLE 1

Chemical Composition of the Waspaloy Forging in Weight Percent

Waspaloy (AMS 5707E) Element Test Forging minimum maximum

Carbon 0.04 0.02 0.10

Manganese 0.10 - 0.10

Silicon 0.10 - 0.15

Phosphorus 0.01 - 0.015

Sulfur 0.004 - 0.015

Chromium 19.10 18.00 21.00

Cobalt 13.50 • 12.00 15.00

Molybdenum 4.40 3.50 5.00

Titanium 3.09 2.75 3.25

Aluminum 1.35 1.20 1.60

Zirconium 0.07 0.02 0.08

Boron 0.005 0.003 0.010

Iron 1.10 - 2.00

Copper 0.10 - 0.10

Nickel Balance Balamce

■19- TABLE 2

Tensile Properties of the Waspaloy Forging at Temperature

Test Te mperature Tensile S1 trength' 0.2% Yie Id Strengh Elongation Reduction of Area ksi (MPa) ksi (MPa) % %

73 (23) 201.7 (1390.7) 148.4 (1023.2) 20.3 33.8 73 (23) 201.3 (1387.9) 149.2 (1028.7) 22.0 37.6 g 800 (427) 183.4 (1264.5) 131.8 (908.7) 19.7 26.7 1 800 (427) 182.1 (1255.5) 132.6 (914.2) 18.7 30.1

1000 (538) 181.2 (1249.3) 126.9 (874.9) 20.0 28.4 1000 (538) 177.2 (1221.8) 120.0 (827.4) 17.8 28.0

1200 (649) 176.1 (1214.2) 124.5 (858.4) 23.7 33.6 1200 (649) 175.3 (1208.7) 117.5 (810.1) 23.1 33.5

1400 (760) 123.9 (854.3) 102.7 (708.1) 22.1 27.2 1400 (760) 124.1 (855.6) 102.9 (709.5) 27.5 45.6 TABLE 3

Fracture Toughness of the Waspaloy Forging at Temperature

Test Temperature Youngs Modulus JJC Fracture Toughness KIC Fracture Toughness o 3 F (°c) 10 ksi (GPa) in-lbs./in. kJ/m2 ksi vfin". MPa\[m" i 73 (23) 32.1 (221.3) 544 (96) 134 (147) £ 73 (23) 32.1 (221.3) 585 (103) 137 i (151) 800 (427) 28.4 (195.8) 434 (76) 111 (122) 800 (427) 28.4 (195.8) 456 (80) 114 (125)

1000 (538) 27.0 (186.2) 434 (76) 108 (119) 1000 (538) 27.0 (186.2) 550 (97) 122 (134) 1200 (649) 26.1 (180.0) 101 (18) 51 (56) 1200 (649) 27.0 (180.0) 110 (19) 53 (58) 1400 (760) 24.4 (168.2) 75 (13) 43 (47) 1400 (760) 24.4 (168.2) 83 (15) 45 (49) - u. ^A> *>•-.,' < "N-J. -1\ - /

•■■/■ ■'

Figure 1 - Microstructure of the fully heat treated Waspaloy forging as viewed in the optical microscope (top) and in the SEM (bottom). Visible are the various sizes of gamma prime precipitates and M23 Cg carbides and coarse gamma prime decorating the gramc boundaries.

-22- Load Line Displacement (mm)

.4 .6 .8

_ 40

8000- i !• .L«;.\' I- 30

6000__ r~\r-.:- CO o ^.L:::i CD ro 7^: .1.:.. 20 ' g 4000 :r::

2000 - 10

.01 .02 .03 Load Line Displacement (in.)

Figure 2 - Typical load versus load line displacement record for a Waspaloy JTr fracture toughness specimen tested at 1200°F (649°C). Temperature (°C) 100 300 500 700

200 - _ | Ultimate Tensile Strength 1400

180 _ _ in c+ 1200 -s 3 t/i in c+ 160 -- rr I no CD i c I. 0.2% Offset Yield Strength 1000 ~ 140 __

120 __ 800

200 400 600 800 1000 1200 1400

Temperature (°F)

Figure 3 - Effect of temperature on the tensile and yield strengths response of the Waspaloy forging. c -I

Strength (ksi)

TO n

3 •o fD ro -S o. DJ o c -s m o. o

r+ ro cri 3 —1 o (/) fD o —!• 3 _J ■a n> ro -5 O) 0J 3 r+ OD Q. c o -s o *< fD —t. CD .—^ —-J o a. -n *. ^ I—" i/i o. r+ CD -s O fD 3 ia rl- S- h-' l/l ro. o -s o ro V) X3 o 3 I-" (/> -p» ro o o o -h r+ ro3" s: 01 i/i •a 0J ^_i o t< -h O (BdW) M^6uau^s -i Id _j* 3 U3 Ol c •r— cn s- o Strength (MPa) 4- >) o n— o o o o rc> o o o o Q. CM o co to (O 3

CU J=+-> 4- o o o CD ■>* 10 i-H c O Q. 10 CU CD s_ O "CM to t-H +J cn c ai o t. o +J "O 10 o i-H ^—^ o Lu ■a O r— CU *■—' i- at >> 13 o s- 4-> "o 3 T3 n3 CO +J C S- rd (0 CU S_ a. CD 0) Q. r— E •r- o cu lO ■o h- c U3 cu +J cu

+J O •o c «* o cu

4-> o fO o s- CM cu CL E cu 4->

4- o 4-> U CU

(j.s>|) i^6u3.ns -24- Temperature (°C) 100 300 500 700

40 A &9 Reduction of Area A "--

•r- 30 - ▲ ro1 r— i •r— A i ■(-> Elongation a ♦ ♦ 20 - _♦" ' ♦ ♦ ♦ ♦

200 400 600 800 1000 1200 1400

Temperature (°F)

Figure 4 - Effect of temperature on the tensile elongation and reduction of area response of the Waspaloy forging. Id C -5 -92- fD

Ductility {%) s: m 01 -h i/> -f> ~U fD ai n —• rt- O << o -h -ti O it- 's in IQ 3 ro ->.-a o i3 ro o in -s • 01 r+ C -s ft) o o o 3 r+ 3" fD -) en r+ fD o fD 3 CD 3 •a to fD _j. -s ~-* QJ fD r+ C 00 ft) -s o —-J fD o O 3 ^—^

O O O CD 3 Q. -S (D ro a. o c o o r+ —I. O 3 O O 01 -s fD 0J -S fD in ■a o 3 l/l fD

3" fD Temperature (°C)

300 500

100

I 75 c o r+ c 10 -s 10 01 c o I j= c CT) 50 m CT) O I I- 0) t/i t. io +J O 7T (0 25 u ■"3

200 400 600 800 1000 1200 1400

Temperature ( F)

Figure 5 - Effect of temperature on the JIC fracture toughness response of the Waspaloy forging. cn £= •1— JTC Fracture Toughness (kJ/ni ) O) s_ 0 o ID o If- o IT) c\i >> ^—0 to Q. 1/1 rO ZS

ai o .c .0 +-> >d- >—< 4- O

ai to O c O 0 1X1 a. 1—1 10 QJ s-

0 CO .0 ai O c !-< .c .^^ C7I o Ll_ 3 o O O * ■ +-> O cu O ai CU S- 00 s_ s_ 3 3 +J +-> (0 ro 0 i- S- ra

O +-> .O «=f 0

QJ i- 3 O +-> .O fO CM S- QJ O.

CU +J

4- 0

0 CU 4- (UL/sqL-UL) ss9UL)6noi gun^oeuj 3*p

■26- QJ S- =1 to c -s fD -92-

JIC Fracture Toughness (in-lbs/in) -h ro o r+ O -h r+ ro 3 ■a n> -5 r\3 a> o" r+ o c 1 fD o 3 r+ o 3" fD

C_i l-H -1 O fD CTl fD 3 O' 3 -h -a O T3 -i fD fD OJ -s -s r> a> m r+ r+ r+ C c C -s -s oo -s fD fD O" fD o r+ »•—*• O o O c TI O UD *«^ 3" I—" 3 CD fD O in O in -5 fD in I—" T3 ro O o 3 o in fD O -h I—• r+ O" 3" o

OJ in •D OJ o << •^1 o O o o -s IQ ( tu/p>j) ss3uu,6noi ajn^oeuj ^p 3* IQ Temperature (°C) 300 500

"# Tn 100- -

10 in 0) c JC I CD O i

s- +J U

600 800 1000 Temperature (°F)

Figure 6 - Effect of temperature on the KJC fracture toughness response of the Waspaloy forging. cn c •r— KjC Fracture Toughness (MPa \fm) Ol 1- o 4- o LT) O in o in o LO >> o p— ro Q. 10 ro 3: 0J o -C o 4-> •3- t-< 4- O

CU m o sz O o OJ Q. t—( m HI s-

o c/1 CD 01 O c <-H en *—■* 3 o u. O o***** -t-> cu o CU i- o a> S- 3 CO i- 3 +-> 3 +J (O 4-> o i- o ro CM i. CU Q. E CU 4->

4- O

4-> O CU 4- 3I (uL|\ LS>|) ssauu6noi a*»n:pe*

-27- CU s- 3 cn lO -s fD -u-

Krp Fracture Toughness (ksi \ffn)

o r+ -e> en co o O -h f—F—F—F—F- TOr+ 3 -oTO -s ro CU o •o r+ o o c 1 CD O =5 o r+ o ZT CD

T; -H CO I—i (D o -f o 3 en o fD ■a o 3 -h fD o T3 -s -5 fD n> 0> -s o r+ CU r+ c r+ c -s oo c -s fD o -s fD o fD r ^ c+ o , , O -n o c ^^^ en o IQ O ». - 3" p—' o 3 o fD o i/i o c/i -s fD 1/) t—' T3 r>o O o (/)3 o fD o O O -h r+ o 3" CO fD ._- CD in TJ _^OJ o << o ro en CD en o en o -h o -s to —It (w_^ PcM) ss3uu,6noi 9*in:peuj ^x =3 ia c J Integral (in-lbs/in) -i m

-J. yo =J i o. o -i. c n -s cu < r+ fD • nj i/i O CL h-" -h r+ O TO -5 3 -o -h n> ->• o • -s < -s o o CU o a' OJ *. fD « 3 l/l _J( r+ 3 ro * i • in o rt- Ul ro D. QJ r+ r+ o =r CT> m

(2WI) Leu6a^ui p Crack Extension (mm) .5 1.0 1.5 2.0

UOr to-,0.U --250 1400L Blunting Line, 73 F (23 C)

73°F {22°tiS 1200_ _ -200