Microstructure and Mechanical Properties of NiTi Alloy Prepared by Double-Wire + Arc Additive Manufacturing Plus In Situ Heat Treatment

作者：Jian Han, Xinya Chen, Guoyang Zhang, Bang Liu, Meiqing Meng, Yangchuan Cai, Hongbing Jiang, Mingjie Bi, Yueqian Hong, Yinbao Tian · 发表于：3D Printing and Additive Manufacturing · 年份：2023 · DOI：10.1089/3dp.2023.0003 · 被引用次数：3 · 研究领域：Shape Memory Alloy Transformations、High Entropy Alloys Studies、Additive Manufacturing Materials and Processes

In this study, NiTi shape memory alloy was prepared by double-wire + arc additive manufacturing plus in situ heat treatment using TA1 and ER-Ni welding wires as the raw materials. The results show that the microstructural evolution from the bottom to top is NiTi 2 + NiTi → NiTi + Ni 3 Ti + Ni 4 Ti 3 → NiTi + Ni 4 Ti 3 + Ni 3 Ti 2 + Ni 3 Ti + α-Ti. Complex thermal cycles led to the precipitation of Ni 3 Ti, which improves the hardness of the matrix (B2), and the average hardness value of the top region reaches 550.7 HV 0.2 . The fracture stress is 2075 ± 138.4 MPa and the fracture strain is 11.2 ± 1.27%. The sample shows 7.02% residual strain and 5.87% reversible strain after 15 cycles, and the stress hysteresis decreases with an increase in cyclic strain.