中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 22 No. 8 August 2012 |
（1. State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering,
Shanghai Jiao Tong University, Shanghai 200240, China;
2. Jiangsu Fasten Company Limited, Jiangying 214400, China;
3. Advanced Materials Technology, Edwards Life Sciences LLC, CA, USA）
Abstract:TiNi and Ti-based shape memory alloys were processed by equal channel angular pressing (ECAP) at 673-773 K along Bc route to obtain ultrafine grains for increasing the strength of parent phase and improving the functional properties. The effects of both thermodynamically stable and metastable second phases on the mechanical properties and martensitic transformations of these alloys were investigated. It is found that thermodynamically stable Ti2Ni phase has no effect on martensitic transformation and superelasticity of Ti-rich TiNi alloy, thermodynamically stable α phase is harmful for ductility of Ti-Mo-Nb-V-Al alloy, but metastable Ti3Ni4 phase is effective for R phase transformation, martensitic transformation and superelasticity of Ni-rich TiNi alloy. The mechanisms of the second phases on the martensitic transformations and mechanical properties were discussed.
Key words: TiNi alloy; Ti-Mo based shape memory alloy; equal channel angular pressing (ECAP); second phase; mechanical property
