Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-10T10:19:24.841Z Has data issue: false hasContentIssue false

Effect of Heat Treatment on the Ductility of Ni(γ)/Ni3Al(γ') Two-phase Alloy Foils

Published online by Cambridge University Press:  26 February 2011

Motonori Nakamura
Affiliation:
Nakamura.motonori@nims.go.jp, University of Tsukuba, Graduate School of Pure and Applied Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 3050047, Japan
Masahiko Demura
Affiliation:
DEMURA.Masahiko@nims.go.jp, National Institute for Materials Science, Fuel Cell Materials Center, 1-2-1 Sengen, Tsukuba, Ibaraki, 3050047, Japan
Ya Xu
Affiliation:
XU.Ya@nims.go.jp, National Institute for Materials Science, Fuel Cell Materials Center, 1-2-1 Sengen, Tsukuba, Ibaraki, 3050047, Japan
Toshiyuki Hirano
Affiliation:
HIRANO.Toshiyuki@nims.go.jp, National Institute for Materials Science, Fuel Cell Materials Center, 1-2-1 Sengen, Tsukuba, Ibaraki, 3050047, Japan
Get access

Abstract

The microstructures and room-temperature tensile properties were examined in the 95% cold-rolled and subsequently heat-treated foils of the boron-free Ni(γ)/Ni3Al(γ') two-phase (Ni-18at.%Al) alloys. The electron backscatter diffraction measurements revealed that the recrystallization started at 873 K/0.5 h and that it completed at 1273 K/0.5 h. While the foils showed no tensile elongation in the cold-rolled state, they became ductile after the heat-treatments at 873 K and above. The tensile elongation increased with the increasing heat-treatment temperature: it reached to 14% at 1273 K/0.5 h. The tensile elongation and the fracture strength were high, compared to those in the γ' single-phase foils. The fracture mode was intergranular, and it changed to a mix of intergranular and transgranular in the foils heat-treated at 1273 K/0.5 h, where the area fraction of crack resistant boundaries such as °1, °3 and °9 was high, 0.63. The high ductility was ascribed to the existence of the ductile γ matrix and to the high fraction of crack-resistant boundaries.

Type
Research Article
Copyright
Copyright © Materials Research Society 2007

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Demura, M, Suga, Y, Umezawa, O, George, EP, Hirano, T. Intermetallics 2001;9:157.Google Scholar
2. Demura, M, Kisida, K, Suga, Y, Hirano, T. Metall Mater Trans A 2002;33A:2607.Google Scholar
3. Demura, M, Kisida, K, Suga, Y, Takanashi, M, Hirano, T. Scripta Mater 2002;47: 267.Google Scholar
4. Borodians' Ka, H, Demura, M, Kisida, K, Hirano, T. Intermetallics 2002;10:255.Google Scholar
5. Li, D, Demura, M, Kisida, K, Suga, Y, Hirano, T. Mat. Rec. Symp. Proc 2003;753: BB5.23.1.Google Scholar
6. Beardmore, P, Davies, RG, Johnston, TL, Transactions of the Metallurgical Society of AIME 1969;245:1537.Google Scholar
7. Harada, H, Yamazaki, M, Koizumi, Y, Testsu-to-Hagane 1979;65:1049.Google Scholar
8. Aoki, K, Izumi, O. Trans Jim 1978;19:203.Google Scholar
9. Cui, C, Demura, M, Kisida, K, Hirano, T. J Mater Research 2005;20:1054 Google Scholar
10. Su, JQ, Demura, M, Hirano, T. Philos. Mag. 2002;82:1541 Google Scholar