医用NiTi合金在激光微连接下的微观组织和力学行为  

Microstructure and Mechanical Behavior of Medical NiTi Alloy by Laser Micro-welding

作　　者：郭志宏[1] 姚润华 胡永金 GUO Zhihong;YAO Runhua;HU Yongjin(College of Material Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学材料科学与工程学院,山西太原030024

出　　处：《热加工工艺》2020年第9期11-14,10,共5页Hot Working Technology

摘　　要：本文利用脉冲激光对钛镍合金丝进行焊接,得到了成型质量良好的焊接接头,在此基础上对钛镍合金焊接接头的微观组织形貌进行了观察并分析了焊接成型过程。此外对钛镍合金焊接接头进行了硬度分布测试,并通过纳米压痕测试从能量变化的角度定量表征了焊接接头各区域的自弹性恢复率。结果表明:焊接过程中熔池在自身重力和润湿作用下沿着丝材接触面流动从而形成接头,焊接接头各区域的晶粒分布状态有明显不同,焊接接头的硬度分布总体呈U型分布,且母材的自弹性恢复率最高,熔化区最低,热影响介于两者之间,这与焊接过程中焊缝组织中生成的金属间化合物阻碍马氏体形变有关。Pulse laser was used to join titanium nickel alloy wires and good welded joint was obtained. On this basis, the microstructure of titanium nickel alloy joint was observed and the welding forming process was analyzed. Moreover, the hardness distribution of joint was measured, and the self-elastic recovery rate of joint in various zone were characteristic through the change of energy by nanoindentation test. The results show that the molten pool flows along the surface under its own gravity and wetting action to form the joint in the welding process. The grain morphology of various zone in welded joint are significantly different. The hardness distribution of joint is ’U’ shape, and the self-elastic recovery rate of base metal is the highest, the fusion zone is the lowest and the heat affected zone is between of them. This result is related to the formation of intermetallic compounds in the microstructure of weld seam during welding.

关 键 词：钛镍合金 激光焊接 微观组织 自弹性恢复率 

分 类 号：TG456.7[金属学及工艺—焊接]