Microstructural design for achieving high performances in Ti-V-Al lightweight shape memory alloys by optimizing Zr content

作者：Xiaoyang Yi, Lijie Sheng, Guoqiang Fu, Bin Sun, Bowen Huang, Kuishan Sun, Xianglong Meng, Zhiyong Gao, Shangzhou Zhang, Haizhen Wang · 发表于：Materials Characterization · 年份：2023 · DOI：10.1016/j.matchar.2023.113283 · 被引用次数：18 · 研究领域：Shape Memory Alloy Transformations、Titanium Alloys Microstructure and Properties、Bone Tissue Engineering Materials

In the present study, the quaternary Zr element was introduced to replace Ti in Ti-V-Al based shape memory alloys. The addition of Zr element resulted in the microstructural features of Ti-V-Al based shape memory alloys, such as the phase evolution of αˊˊ → β, the precipitation of C14-type Laves phase, reduction of grain size etc. Moreover, the two-stage martensitic transformation corresponding to ω → β and αˊˊ → β transformation gradually evolved into single ω → β martensitic transformation during heating process in Ti-V-Al based shape memory alloys, as Zr content was increased from 0.5 at.% to 5.0 at.%, which was firstly reported in Ti-V-Al based shape memory alloys. Meanwhile, the martensitic transformation temperatures of Ti-V-Al based shape memory alloys were decreased with Zr increasing. By optimizing Zr content, the highest yield strength and largest microhardness can be gained in Ti-V-Al based shape memory alloy with controlling 5.0 at.% Zr, as a result of solution strengthening, grain refinement and precipitation strengthening. Besides, the moderate Zr content caused the precipitation of C14-type Laves phase and formed the quasi-continuous network structure, which contributed to the superior elongation. And the perfect fracture ductility with an elongation of 40% in the present Ti-V-Al based shape memory alloys with 3.0 at.% Zr was significantly larger than that the other reported Ti-V-Al based shape memory alloys. Moreover, the superior strain recovery characteristi...