Online ISSN : 1347-5320
Print ISSN : 1345-9678
ISSN-L : 1345-9678
Twinning Induced Plasticity and Work Hardening Behavior of Aged Cu–Ni–Si Alloy
Akiyoshi ArakiWarren J. PooleEquo KobayashiTatsuo Sato
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2014 Volume 55 Issue 3 Pages 501-505


The work hardening behavior and deformed microstructure of the Cu–Ni–Si alloy aged at 723 K for various times and then deformed at 293 and 77 K were extensively investigated. The precipitate microstructure was also observed using transmission electron microscopy after aging treatment at 723 K for 0.30, 3.6, 64.8 and 345.6 ks. Deformation twins were clearly observed by transmission electron microscopy in the under-aged specimen deformed by 10% in tension at 293 K, in accordance with the enhanced work hardening rate observed during tensile deformation. The thickness of the deformation twins observed was approximately 1–40 nm. In addition, a significant fraction of larger deformation twins were observed by EBSD on the surface of the under-aged and peak-aged specimens tested at 77 K, for which the stress–strain behavior exhibited a nearly constant work hardening rate, i.e., high tensile strength and high elongation. These results show that the deformation twins formed during tensile deformation at 293 K contribute to strengthening of the specimen as new obstacles to the dislocation slip. Moreover, the enhanced twinning deformation at 77 K achieves high strength and elongation in the under-aged and peak-aged conditions. On the other hand, only a few deformation twins were observed in the supersaturated solid solution and over-aged specimens.

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© 2014 The Japan Institute of Metals and Materials
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