激光焊接对Ni-49at%Ti微观组织和力学性能的影响(英文)  

Effect of Laser Welding on Microstructure and Mechanical Behavior of Ni-49at%Ti

作　　者：郭伟[1] 宋鹏[1] 朱颖[1] 曲平[1] 康慧[1] 王海燕[1] 

机构地区：[1]北京航空航天大学,北京100191

出　　处：《稀有金属材料与工程》2013年第S2期78-82,共5页Rare Metal Materials and Engineering

基　　金：The Fundamental Research Funds for the Central Universities

摘　　要：采用激光焊接NiTi形状记忆合金,分别对母材和焊缝区域的显微组织、显微硬度、相构成、相变行为、力学性能和断口形貌进行对比研究。结果表明:焊缝中心区的显微组织为粗大的柱状晶,热影响区和母材的显微组织为晶粒大小基本相同的等轴晶。焊缝区域的显微硬度与母材相比没有发生明显的变化。焊缝区域室温下的相构成与母材相同,激光焊接接头的相变顺序和相变温度与原始母材相比,都发生了改变。焊缝的极限抗拉强度为511 MPa,达到母材的49.4%。母材的断裂模式为韧性断裂,而焊缝的断裂模式为脆性断裂。在超弹性测试实验中,焊缝保留了较多的残余变形,说明激光焊接降低了NiTi合金超弹性性能。The experiment of laser welding of NiTi shape memory alloys was performed.The microstructure,micro-hardness,phase constituent,phase transformation behavior and mechanical behavior of both the joint and base metal were investigated.The results show that the microstructure of the fusion zone is coarse columnar crystals and the microstructure of HAZ and base metal is equiaxed crystals.The phase constituent of the joint have no significant difference compared with the base metal at room temperature.The phase transformation order and temperature of the laser welding joint is different from that of the base metal.The ultimate tensile strength of the joint is 511 MPa,which achieves 49.4% of the base metal.The fracture mode of the base metal is ductile type,while the fracture mode of the joint is brittle type.The joint reserves more residual strain than the base metal in the superelastic measurements.

关 键 词：NITI 激光焊 力学性能 马氏体相变行为 

分 类 号：TG456.7[金属学及工艺—焊接]