The results from a series of elevated temperature prestrain experiments on a hypostoichiometric polycrstalline Ni3Al are presented. Experiments were conducted to examine the deformation characteristic of “thermal reversibility” or temperature path history independence (TPHI). Temperature path history independence was experimentally observed from prestraining experiments (also known as Cottrell-Stokes experiments) in which the specimen was deformed at different temperatures; the results were compared to those obtained from tests conducted at constant temperature. The purpose of such experiments was to macroscopically evaluate the effects of intrinsic dislocation mobility and dislocation substructure on deformation. These experiments provide a framework in which to evaluate fundamental characteristics of thermally activated deformation processes. The results for polycrystalline Ni3Al alloys indicate that the mechanisms responsible for thermal strengthening is independent of prior deformation history. This observation implies that the mechanism of anomalous strengthening in such alloys is fully reversible and independent of the development of a dislocation “substructure”.

1.
Takeuchi
S.
, and
Kuramoto
E.
,
Acta Metallurgica
, Vol.
21
,
1973
, pp.
415
42
.
2.
Lall
C.
,
Chin
S.
, and
Pope
D. P.
,
Metallurgical Transactions A
, Vol.
10A
,
1979
, pp.
1323
1332
.
3.
Paidar
V.
,
Pope
D. P.
, and
Vitek
V.
,
Acta Metall.
, Vol.
32
,
1984
, pp.
435
48
.
4.
Webb
Graham
,
de Bussac
Arnaud
, and
Antolovich
Stephen D.
,
Met. Trans.
, Vol.
24A
,
1993
, pp.
397
401
.
5.
Veyssiere
P.
,
Guan
D. L.
, and
Rabier
J.
,
Philosophical Magazine A
, Vol.
49
, No.
4
,
1984
, pp.
45
54
.
6.
Sun
Y. Q.
, and
Hazzledine
P. M.
,
Philosophical Magazine A
, Vol.
A58
,
1988
, pp.
603
618
.
7.
Mills, M. J., Baluc, N., Karnthaler, H. P., Liu, C. T., Taub, A. I., Stoloff, N. S., and Koch, C. C. eds. “High-Temperature Ordered Intermetallic Alloys III,” Vol. 133, 1989, pp. 203–208.
8.
Veyssiere, P., Liu, C. T., and Taub, A. I., and Stoloff, N. S., and Koch, C. C., eds., High Temperature Ordered Intermetallic Alloys III, Materials Research Society, 1989, pp. 175–187.
9.
Caillard
D.
,
Clement
N.
,
Couret
A.
,
Lours
P.
, and
Coujou
A.
,
Philosophical Magazine A
, Vol.
58
, No.
6
,
1989
, pp.
263
269
.
10.
Taub
A. I.
,
Chang
K. M.
, and
Liu
C. T.
,
Scripta Metallurgica
, Vol.
20
,
1986
, pp.
1613
1618
.
11.
Dimiduk, D., WRDC-TR-89-4106, 1989.
12.
Dowling, Jr., W. E., and Gibala, R., Liu, C. T., Taub, A. I., Stoloff, N. S., Koch, C. C., eds., “High Temperature Ordered Intermetallic Alloys III,” Vol. 133, Materials Research Society, 1989, pp. 209–215.
13.
Hemker, K., Ph.D. dissertation, Stanford University, 1990.
14.
Hirsch, P. B., Howie, A., Nicholson, R. B., Pashley, D. W., and Whelan, M. J., Electron Microscopy of Thin Crystals, Butterworths, London, 1965.
15.
Thorton
P. H.
,
Davies
R. G.
, and
Johnston
T. L.
,
Metallurgical Transactions
, Vol.
1
,
1970
, pp.
207
218
.
16.
Baker
I.
, and
Schulson
E. M.
,
Physical States of Solids (a)
, Vol.
89
,
1985
, pp.
163
172
.
17.
Suzuki
K.
,
Ichihara
M.
, and
Takeuchi
S.
,
Acta Metallurgica
, Vol.
27
,
1979
, pp.
193
200
.
18.
Veyssiere
P.
,
Douin
J.
, and
Beauchamp
P.
,
Philosophical Magazine A
, Vol.
51
,
1985
pp.
469
483
.
19.
Milligan, W. M., and Antolovich, S. D., NASA Contractor Report 4215, 1989.
20.
Yamaguchi
M.
,
Paidar
V.
,
Pope
D. P.
, and
Vitek
V.
,
Philosophical Magazine A
, Vol.
A45
,
1982
, pp.
867
882
.
21.
Paidar
V.
,
Yamauchi
M.
,
Pope
D. P.
, and
Vitek
V.
,
Philosophical Magazine A
, Vol.
A45
,
1982
, pp.
883
894
.
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