Effect of Nb on M-A Phase Transition Temperature of NiTi Micro-Laser Weld [Nb对NiTi微激光焊缝组织M-A相变温度的影响]

摘要

In order to obtain a 0.2 mm-thick NiTi shape memory alloy (NiTi-SMA) welded joint with a small difference in phase transformation temperature between the welded metal and the base metal, it will meet the needs of practical applications. In this paper, the Nb element is introduced into the weld by adding welding wire, and the welded joint is aging treated after welding to realize the control of the weld metal phase transition temperature, so that it can reach a level similar to that of the base metal. The results show that the weld metal of NiTi joint with Nb wire is mainly B2 phase, B19'phase, NbTi phase, Nb phase and (NiTi, Nb) solid solution, and Ni4Ti3 phase precipitates from weld metal after PWHT at 600℃. Through the compound method of "adding 0.10mmNb wire+ PWHT at 600 ℃", weld metal with As and Ms very close to that of NiTi base metal was obtained.

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