Achieving large super-elasticity through changing relative easiness of deformation modes in Ti-Nb-Mo alloy by ultra-grain refinement

• Main Authors: Bingjie Zhang, Mingda Huang, Yan Chong, Wenqi Mao, Wu Gong, Ruixiao Zheng, Yu Bai, Dong Wang, Qiaoyan Sun, Yunzhi Wang, Nobuhiro Tsuji
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2021-05-01
• Series: Materials Research Letters
• Subjects: super-elasticity; yielding behavior; deformation-induced martensitic transformation; dislocation slip; in-situ synchrotron radiation x-ray diffraction
• Online Access: http://dx.doi.org/10.1080/21663831.2021.1875080
• ISSN: 2166-3831

Large super-elasticity approaching its theoretically expected value was achieved in Ti-13.3Nb-4.6Mo alloy having an ultrafine-grained β-phase. In-situ synchrotron radiation X-ray diffraction analysis revealed that the dominant yielding mechanism changed from dislocation slip to martensitic transformation by decreasing the β-grain size down to sub-micrometer. Different grain size dependence of the critical stress to initiate dislocation slip and martensitic transformation, which was reflected by the transition of yielding behavior, was considered to be the main reason for the large super-elasticity in the ultrafine-grained specimen.