Haynes 188, A EECTE G1J - DTICHaynes 188 Introduction Haynes 188 alloy combines excellent high temperature strength with very good resistance to oxidizing environments up to 1095 C

AD-A268 355 8 0 /C

Atlas of Formability;'

Haynes 188,

EECTEA G1819931J .

NCEM

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ATLAS OF FORMABILITY

HAYNES 188

by

Prabir K. Chaudhury and Dan Zhao

National Center for Excellence in Metalworking Technology1450 Scalp Avenue

Johnstown, PA 15904

for

Naval Industrial Resource Support ActivityBuilding 75-2, Naval Base

Philadelphia, PA 19112-5078

February 28, 1993

The views, opinions, and/or findings contained in this report are those of the authors and should not be

construed as an official Department of the Navy position, policy, or decision, unless so designated by

other documentation

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"1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVEREDFebruary 28, 1993 Final, Nov. 30, 1992 - Feb. 28, 1993

4. TITLE AND SUBTITLE S. FUNDING NUMBERS

ATLAS OF FORMABILITY C-N00140-88-C-RC21HAYNES 188

6. AUTHOR(S)

Prabir K. ChaudhuryDan Zhao

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATIONREPORT NUMBER

National Center for Excellence in Metalworking Technology (NCEMT)1450 Scalp AvenueJohnstown, PA 15904

9. SPONSORING,' MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/ MONITORING

AGENCY REPORT NUMBER

Naval Industrial Resources Support ActivityBuilding 75-2, Naval BasePhiladelphia, PA 19112-5078

11. SUPPLEMENTARY NOTES

1Za. DISTRIBUTION / AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

In this investigation, flow behavior of Haynes 188 alloy was studied by conducting compression testsover a wide range of temperatures (950 - 1200 C) and strain rates (0.001 - 20 s-1 ). The true stress-truestrain flow curves are presented for each test condition. Constitutive relations were determined from theflow behavior, and a dynamic material modeling was performed on this alloy. Thus, the optimumprocessing condition in terms of temperature and strain rate was identified as 1100 C and 0.001 s- 1 forthis alloy. Microstructural changes during high temperature deformation were also characterized, andselective micrographs are presented together with corresponding flow curves. Dynamic recrystallizationand grain growth occurred during high temperature deformation over the range of temperatures tested.This report supplies ample mechanical and microstructural data on Haynes 188 alloy for engineers inthe field of metalworking process design. The data presented here are also very helpful in finite elementanalysis of metalworking processes.

14. SUBJECT TERMS 15. NUMBER OF PAGES

Haynes 188, Deformation Processing, High Temperature Deformation, 16. pEt CODEProcessing Map, Metalworking, Deformed Microstructure

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACrOF REPORT OF THIS PAGE OF ABSTRACT

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TABLE OF CONTENTS

Introduction ................................... 1

Experimental Procedure ............................ 1

Results ....................... ............... 1

Summary .................................... 64

Implementation of Data Provided by the Atlas of Formability ........ 64

Aooession For

OTIS GRA&I EKDTIC TAB DUnannounced oJustificatlon

ST #A, AUTH USNAVIRSA (MR PLONSKY 8/443-6684) By

PER TELECON, 17 AUG 93 CB itributi on/

Availability Codesnnlt Avail and/or---Dlt special

LIST OF TABLE

Table 1. List of figures, testing conditions and microstructural observationsfor Haynes 188 ....... ................................. 2

fi

Haynes 188

Introduction

Haynes 188 alloy combines excellent high temperature strength with very good resistance tooxidizing environments up to 1095 C. The alloy also has good forming and welding characteristics,but work-hardens rapidly. The understanding of mechanical and microstructural behavior during hightemperature deformation is very important for the forming processes of this material. In thisinvestigation, flow behavior of Haynes 188 was studied by conducting compression tests over a widerange of temperatures and strain rates. Constitutive relations were determined from the flow behaviorand subsequently, a dynamic material modeling for this alloy was performed. Thus, the optimumprocessing condition in terms of temperature and strain rate was determined. Microstructural changesduring high temperature deformation were also characterized to help process design engineers selectprocessing conditions for desired microstructure.

Experimental Procedure

The material used in this investigation was commercially available Haynes 188 wrought bars inannealed condition with approximately 16 mm diameter. The typical microstructure of the as-receivedmaterial is shown in Figure 1. The chemical composition is as follows (wt%, bal. Co):

C S Mn Si Cr B Fe Ni W P

0.11 <0.002 0.78 0.41 22.04 0.004 2.20 22.67 13.81 0.014

Cylindrical compression test specimens with a diameter of 12.7 mm and a height of 15.9 mmwere machined from the bars. Isothermal compression tests were conducted in vacuum on an MTStesting machine. The test matrix was as follows:

Temperature, C (F): 950 (1742), 1000 (1832), 1050 (1922), 1100 (2012), 1150 (2102), 1175(2147), and 1200 (2192);

Strain rate, s-1: 0.001, 0.01, 0.05, 0.1, 0.5, 1, 5 and 20.

Load and stroke data were acquired during the tests by a computer and later converted to truestress-true strain curves. Immediately after the compression test, the specimens were quenched withforced helium gas in order to retain the deformed microstructure. Longitudinal sections of thespecimens were examined by optical microscopy. The photomicrographs were taken from the centerof the longitudinal section of the specimens.

Results

Table 1 is a list of the figures, test conditions, and the observed microstructures. The truestress-true strain flow curves with selective corresponding deformed microstructure are shown inFigure 2 to Figure 57. True stress versus strain rate was plotted in log-log scale in Figure 58 at a truestrain of 0.5. The slope of the plot gives the strain rate sensitivity m, which is not constant over therange of temperatures and strain rates tested. Log stress vs. I/T at the same true strain is shown inFigure 59. A processing map at this strain was developed and is shown in Figure 60. The optimumprocessing condition from the map can be obtained by selecting the temperature and strain ratecombination which provides the maximum efficiency in the stable region. This condition isapproximately 1100 C and 10-3 s- 1 for this material.

I

Table 1. List of figures, testing conditions and microstructural observations for Haynes 188.

Figure Temperature Strain Rate Microstructure PageNo C (F) s-I No

Optical MicroscopyI As received Equiaxed grains with an average size of 54.4 gun, 4

multiple twins in some grains and presence ofprecipitates.

2 950(1742) 0.001 Deformed grains with an average size of 59 m, 5-30% dynamically recoystallized (DRX) grains with<2 jum in size surrounding the large deformedgrains, presence of fine precipitates.

3 950(1742) 0.01 64 950 (1742) 0.05 Same as above, but with some twins. 75 950(1742) 0.1 Elongated grains with an average size of 55.3 un, 8

-20% recrystallized grains with < 2 min in size.6 950 (1742) 0.5 97 950(1742) 1 Severely deformed grains with - 5001 DRX grains 10

(<2 pm in size) and some neckacing at the grainboundaries.

8 950(1742) 5 119 950(1742) 20 Same as above, but with less amount of 12

rectystallized grains (-10%) and presence ofsubstructure.

10 1000(1882) 0.001 Deformed grains with serrated boundaries and 13-100% substructure formation.

11 1000(1882) 0.01 Same as above but with less substructure formation. 1412 1000(1882) 0.05 1513 1000(1882) 0.1 1614 1000(1882) 0.5 Severely deformed grains with -80% DRX (< 4 pm 17

grain size) presence of deformed original grainboundaries.

15 1000 (1882) 1 Same as above. 1816 1000(1882) 5 1917 1000(1882) 20 Same as above but with -60% DRX 2018 1050 (1922) 0.001 -90% DRX (-8 pam grain size), the deformed 21

original grain boundaries hardly visible.19 1050(1922) 0.01 2220 1050(1922) 0.05 Large severely deformed grains with -80% DRX, 23

presence of defonned origiani grain boundaries.21 1050 (1922) 0.1 2422 1050 (1922) 0.5 2523 1050(1922) 1 Same as above, but with less amount of DRX 2624 1050(1922) 5 Same as above. 2725 1050(1922) 20 Same as above. 2826 1100(1212) 0.001 100% DRX equiaxed grains (average grain size of 29

8.2 * 0.9 jim).27 1100(1212) 0.01 Same as above, but with a larger grain size. 3028 1100(1212) 0.05 3129 1100(1212) 0.1 100% DRX equiaxed grains (7.7 :k 0.7 jam in size) 32

within the large deformed originalgrains.30 1100(1212) 0.5 1 3331 1100(1212) 1 -So0. DRX grains (-6.5 pmn in size) within the 34

large deformed grains, some substructure formation.

2

32 1100(1212) 5 3533 1100(1212) 20 100% DRX equiaxed grains (-6.1 p&m in size) 36

within the sverl deformed s34 1150(2102) 0.001 100% DRX grains (-40 ;un in size), some multiple 37

twins and evenly dispersed fine precipitates.35 1150(2102) 0.01 Same as above, but with-25 Mn DRX grains. 3836 1150(2102) 0.05 3937 1150(2102) 0.1 4038 1150(2102) 0.5 100% equiaxed unirorm sized grains with no 41

evidence of prior grain boundaries.39 1150(2102) 1 Same as above but with-15 jAm DRX grain size. 4240 1150(2102) 5 4341 1150(2102) 20 Same as above, but with -10 tun in grain size and 44

some twinning.42 1175(2147) 0.001 100% DRX and grown grains with -55 Pn in size, 45

some multiple twinning and evenly distributed fineprecipitates.

43 1175 (2147) 0.01 4644 1175(2147) 0.05 Same as above, but with -20 jin grain size. 4745 1175 (2147) 0.1 4846 1175 (2147) 0.5 4947 1175 (2147) 1 100% DRX with non-uniform sized grains (average 50

-15 run), multiple twins in some grains and evenlydistributed fine precipitates.

48 1175 (2147) 5 Same as above with more regular grain size. 5149 1175 (2147) 20 Same as above with even more uniformly sized 52

owrains.50 1200 (2192) 0.001 100% DRX and grown equiaxed grain with an 53

average size of 67.6 * 15.7 lun, multiple twins insome grains and considerably less amount of fineprecipitates.

51 1200 (2192) 0.01 Same as above, but with smaller (-40 Pam) DRX 54grain size.

52 1200(2192) 0.05 5553 1200 (2192) 0.1 100% DRX and grown non-uniform sized grains 5654 1200(2192) 05 (average -30.5 + 3.4 pam) with much twinning. 5754 1200 (2192) 0.5 _______ _________57

55 1200(2192) 1 Same as above with - 30 Pin grain size. 5856 1200 (2192) 5 5957 1200(2192) 20 Same as above with - 26* 1.9 ýn grain size. 60

3

Figure 1. As-received mnicrostructure, of Haynes 188.

300, ,

Haynes 1 88

250

o_ 200

U)1 50

L_

: 100I-

50 Temperature: 950 CStrain Rate: 0.001 s-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

501m

Figure 2. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 950 C and 0.001 s-1I

5

4-50

Haynes 1 88

,__ 350

Ci 250Q)

4-1-

• 1501--

Temperature: 950 C50 Strain Rate: 0.01 s-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 3. True stress-true strain curve, 950 C and 0.01 s- 1.

6

500, ,

Haynes 1 88

400

0a

v- 300U)4-0

o 200

100 Temperature: 950 C

Strain Rote: 0.05 --1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 4. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 950 C and 0.05 s-1.

7

600 , ,

Haynes 1 88500

a 400

CO

Q 300L.

4a

(n)(D 200

I--

100 Temperature: 950 CStrain Rate: 0.1 a-1

0 * I I 1 I I , I * I * I

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 5. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 950 C and 0. 1 s-

8

700 , ,

Haynes 188600

500

400 -

2! 300

=30

2001

100 Temperature: 950 CStrain Rate: 0.5 a- 1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 6. True stress-true strain curve, 950 C and 0.5 s-1.

9

700 , ,

Hoynes 1 88600

o' 5000_

, 400CO

-b 300

i.- 200

10O0 Temperature: 950 CStrain Rate: 1.0 3-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 7. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 950 C and I s-1

10

K,'Lp- 7.00

Haynes 1 88600

500r•

S400

-- 300

L- 200


0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 8. True stress-true strain curve, 950 C and 5 s-1.

II

800 , , , , ,700 Haynes 188700

,, 600

M 500

2 400

S30oo

I- 200

100 -Temperature: 950 C

Strain Rate: 20.0 s-1

0I I * I , I

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 9. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 950 C and 20 s-1.

12

300 , , •Haynes 1 88

250

o_ 200

CO'S 150

100 0

50 Temperature: 1000 CStrain Rate: 0.001 3-1

00.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 10. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1000 C and 0.001 s- 1.

13

"400

Haynes 188

320

240

U) 160

1,..


Strain Rate: 0.01 sr-

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

501Lm


14

500

Haynes 1 88

400

C-*v 300(nU,D

L.t

U) 200

1.~


Strain Rate: 0.05 s-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain


15

500

Hoynes 1 88

400

•-' 300CD

UA 200


Strain Rote: 0.1 s-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 13. True stress-true strain curve, 1000 C and 0. 1 s'1.

16

600Haynes 188

500

Q- 400

(D 300

S 200


0 1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 14. True stress-true strain curve and an optical mnicrograph from the center of the compressed

sample cut through the compression axis, 1000 C and 0.5 s-1 .

17

600 , ,

Haynes 188

500I:,,

- 400 0

p 300

S200

100 Temperature: 1000 CStrain Rate: 1.0 3-1

O0 o 1, , , I0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

501Lm

Figure 15. True stress-true strain curve and an optical micrograph from the center of the compressed

sample cut through the compression axis, 1000 C and I s-1 .

18

600 , , , , , ,

Haynes 188500

CL 400

Co(D 300L.

4-0-

3 200


O0 1 .- I . - I I

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 16. True stress-true strain curve, 1000 C and 5 s-.

19

800 , ,

7 Hoynes 1 88700-

600CL

S500

( 400L.

03 300

•- 200Temperature: 1000 C

10 Stroin Rate: 20.0 s1

00.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain


20

200 , , , .

Haynes 1 88

1500~

Cn

n 100

I-..- 50

Temperature: 1 050 CStrain Rate: 0.001 s-1

0 1 . I ., I ,

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 18. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1050 C and 0.001 s"1.

21

300Haynes 1 88

250

0 20 200

Q 150L.

=3 100

50 Temperature: 1 050 CStrain Rate: 0.01 s1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain


22

Haynes 188

S300

• 200L.o

Cl)

P- 100Temperature: 1050 CStrain Rate: 0.05 s-1

0 J I * I * I p I , * I I

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 20. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1050 C and 0.05 s-.

23

400 , ,

Haynes 1 88

,- 3000 2

(DG'3< 200

-I-

I-100

Temperature: 1050 CStrain Rate: 0.1 s-1

0. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain


24

500Haynes 1 88

400

- 300C/3

S200

1.~

100 Temperature: 1 050 C

Strain Rate: 0.5 a-1O0 1 1 . -I , .

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain


25

500 , ,

Haynes 188

400

300

L.

200

0)O


Strain Rate: 1 .0 a-1

0 1 - . I . I I

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 23. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1050 C and I s-1.

26

600 *

.Haynes 1 88500

~- 400

D 2300L-4

S200

100 -Temperature: 10500CStrain Rate: 5.0 s-1

00.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 24. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut throughi the compression axis, 1050 C and 5 s-1.

27

700 0 , , ,Haynes 1 88

600

500

u 400

S300

L- 200

1Temperature: 1050 C100 Strain Rate: 20.0 s-1

O0 1 1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

5%Lm


28

150

Haynes 1 88

120

S 90U3

L. 1) 601=I3


0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

501m

Figure 26. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1100 C and 0.001 s-1 .

29

200 , ,

Haynes 1 88

150

Q 100

I- 50Temperature: 1100 CStrain Rate: 0.01 s-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

501Pm

Figure 27. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1100 C and 0.01 s- 1.

30

300Haynes 1 88

250 -

o_ 200

U3@ 150L.

100 0


0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain


31

300 , . ,Hoynes 1 88

250

o_ 200

< 150

:31 00


O0 1 1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

501Lm

Figure 29. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1100 C and 0. 1 s'-

32

400 0 *

Haynes 188

300

q 200

I- 100

Temperature: 1100 CStrain Rate: 0.5 a-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 30. True stress-true strain curve, 100 C and 0.5 s-1 .

33

400 , *

Haynes 1 88

300a-

(D 200L.

:3)

I- 100


O0 1 1 1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

501zm

Figure 3 1. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1100 C and I s-1.

34

500 , ,

Haynes 1 88

400

300

200


Struin Rate: 5.0 s-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Figure 32. True stress-true strain curve, 1100 C and 5 s-1.

35

600Hoynes 1 88

500

. 4-00

q) 300

S200

100 Temperature: 1100 CStrain Rate: 20.0 s-I

00.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 33. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1100 C and 20 s".

36

100 *

.Hoynes 188

80

*•-' 60U]Uf)

40


Strai• Rate: 0.001 s-1

O0 1 1 1 . I I ,

00 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

5N


sample cut through the compression axis, 1150 C and 0.001 s-1.37

Haynes 1 88

120

90 ' 9

L.

60

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 3 5. True stress-true strain curve and an optical midcrograph from the center of the compressedsample cut through the compression axis, 1150 C and 0. 01 s-.

38

200 ..

Haynes 188

"150

ff 100

(')

50Temperature: 1150 CStrain Rate: 0.05 s-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain


39

250 , ,

Haynes 188

200

%-,150cn

S1oo0

50 Temperature: 11 50 C

Stroan Rote: 0.1 a-100 . , , , , ,. --I . I

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 37. True stress-true strain curve, 1150 C and 0.1 S-1.

40

300 , ,

Hoynes 188250

o_ 200

CnS 150

L.

:3 100I-

50 Temperature: 1150 CStruin Rate: 0.5 s-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

501Lm


41

400Haynes 1 88

300

S200t-I

LF- 100Temperature: 1150 CStrain Rate: 1.0 a-0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

501L

Figure 39. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1150 C and 1 s 1.

42

4.00 0 ,

Haynes 1 88

'-, 300

QC-

p, 200U-

0):3

•- 100Temperature: 1150 CStrain Rate: 5.0 a-'

0 L0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 40. True stress-true strain curve, 1150 C and 5 s-.

43

500

Haynes 188

400

0300

U3

CD

200


Strain Rote: 20.0 s-1

0 l l 1 I I l l I - . I I I0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 41. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1150 C and 20 s.

44

100 *

Hoynes 188

80

%-.' 60

44-0

20STemperature: 1 175 CStrain Rate: 0.001 s-1

00 , 1 , -,. , . , . I I00 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

5%L

Figure 42. True stres-tre strain curve and an optical micrograph from the center of the compressedsample cut 20 roug the compression aCis, 1175 C and 0.0011 s-

45

150

Haynes 188

120O

a-S90

CD,

,4-, 60

L.I--

30 Temperature: 11 75 CStrain Rate: 0.01 s-1

o f -I- I . -I . . I

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 43. True stress-true strain curve, 1175 C and 0.01 s-I.

46

200

Haynes 1 88

500- 5

Temperature: 11 75 CStrain Rate: D.05 s-I

0 101

0.0• 0.1 0.2 0.3 0.4 0.5 0,6 0.7 0.8

True Strain

Figure 44. True stress-true strain cure and an optical micrograph from the center of the compressedsample cut through the compression axis, 1175 C and 0.05 $-1.

47

0 *II iii I III i I * 1 ii

200 , ,

Haynes 1 88

"• 1500~CL

U3

e 100

C")=3

S- 50Temperature: 1175 C

Strain Rate: 0.1 a-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 45. True stress-true strain curve, 1175 C and 0.1 s- 1.

48

300 , ,

Hoynes 1 88250

0

oL 200

W 150

U)G> 100

50 Temperature: 1175 CStrain Rote: 0.5 sa1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain


49

300Hoynes 1 88

250

a- 200

1•50U)V 1 O0

S 100

50 Temperature: 1175 CStrain Rote: 1 .0 a-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

50p1m

Figure 47. True stress-true grain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1175 C and I s-1.

50

400 * *

Haynes 1 88

S' 300

0~=3

S200

I- 100Temperature: 1175 CStrain Rate: 5.0 s-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

501•m


51

4-00

Haynes 1 88

,'-, 300

Q 200

L_

S100 -

Temperature: 1175 CStrain Rate: 20.0 3-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain


52

80 * *

Haynes 1 88

60

• 40

20


0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

!501Lm

Figure 50. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1200 C and 0.001 s 1 .

53

150 *

.Haynes 188

120

9000n

U) 6


Strain Rate: 0.01 w-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 5 1. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1200 and 0.01 s-1.

54

150 , . ,

Haynes 1 88

120

• 90

C) 601.!


Strmin Rate: 0.05 s-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain


55

200 , ,

Haynes 1 88

150

:35 00

Temperature: 1 200 CStrain Rate: 0.1 a-1

00 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

-I-I

Figure 53. True stress-true strain curve and an optical micrograph from the center of the compressedsample cut through the compression axis, 1200 and T. 1 s-1.

56

300Haynes 1 88

250

0._ 200

g 150

100 0


0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

Figure 54. True stress-true strain curve, 1200 and 0.5 s-1 .

57

300i. Haynes 1 88

250

C- 200

E 150,4-,

UI)

:3 1001

50 Temperature: 1200 CStrain Rate: 1 .0 s-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain

501•m


sample cut through the compression axis, 1200 and 1 s-

58

400 , , '

Haynes 1 88

300

200

100Temperature: 1200 CStrain Rote: 5.0 a-1

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Figure 56. True stress-true strain curve, 1200 and 5 s-1.

59

400 . . .

Haynes 1 88

•-' 300

Q 200L.

-4-P

I- 100


0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

True Strain


sample cut through the compression axis, 1200 and 20 s-1.

60

103

Haynes188

A

CL AC80 U AA"a. A U 100A

13 Temperature (C)_• 102 A v0) 950

a Q , 1000:3 1050

0 1100A 1150o 1175v 1200

101 a a kIIII a .10-3 10-2 10-1 100 101

Strain Rate (s-1)

Figure 58. Effect of strain rate on stress in log-log scale at a true strain of 0.5 for Haynes 188.

61

1 03

Haynes 188

9A

Q0 0Av v

3 A

D 102 * Strain Rate (a-')-~~ AA

CI) * 0.001• * A 0.01

M 0.05

+ 0.5* 1.0v 5.00 20.0

101 I i ,/i(, n , /K, 0.1

0.65 0.68 0.72 0.75 0.78 0.82 0.851/ b(1 O00/K)

Figure 59. Effect of temperature on stress at a true strain of 0.5 for Haynes 188.

62

Haynes 1 88

0

30.

C,)

O -2-j

950 1000 1050 1100 1150 1200Temperature (C)

Figure 60. Processing mnap of Haynes 188 at a true strain of 0.5.

63

Summary

Compression tests have been performed on Haynes 188 over a wide range of temperatures andstrain rates. The experimental conditions used in this work are representative of those inmetalworking practice. From the true stress-true strain curves, the flow behavior was characterizedand a processing map indicating the optimum processing condition was generated. This condition is1100 C and 10-3 s-1 .

The deformed microstructures were characterized from the quenched specimens by opticalmicroscopy and are presented for selective testing conditions together with the stress-strain curves.

Implementation of Data Provided by the Atlas of Formability

The Atlas of Formability program provides ample data on flow behavior of various importantengineering materials in the temperature and strain rate regime commonly used in metalworkingprocesses. The data are valuable in design and problem solving in metalworking processes ofadvanced materials. Microstructural changes with temperature and strain rates are also provided inthe Bulletin, which helps the design engineer to select processing parameters leading to the desiredmicrostructure.

The data can also be used to construct processing maps using the dynamic material modelingapproach to determine stable and unstable regions in terms of temperature and strain rate. Thetemperature and strain rate combination at the highest efficiency in the stable region provides theoptimum processing condition. A processing map has been developed in this Bulletin. In somemetalworking processes, such as forging, strain rate varies within the workpiece. An analysis of theprocess with finite element method (FEM) can ensure that the strain rates at the processingtemperature in the whole workpiece fall into the stable regions in the processing map. Furthermore,FEM analysis with the data from the Atlas of Formability can be coupled with fracture criteria topredict defect formation in metalworking processes.

The data provided by the Atlas of Formability are used in the design of metalworkingprocesses, dynamic material modeling, FEM analysis of metalworking processes, and defect predictionat Concurrent Technologies Corporation. CTC can apply its expertise in metalworking area to solverelated problems. For more information, please contact Dr. Prabir K. Chaudhury, Manager ofForming Department, by calling (814) 269-2594.

64

Documents

Haynes 188, A EECTE G1J - DTICHaynes 188 Introduction Haynes 188 alloy combines excellent high temperature strength with very good resistance to oxidizing environments up to 1095 C