Microstructure and mechanical properties of laser beam welded TC4/TA15 dissimilar joints

作     者：Wei-feng XU Zhen-lin ZHANG 徐韦锋;张振林

作者机构：State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi’an 710072 China Shaanxi Key Laboratory of Friction Welding TechnologiesNorthwestern Polytechnical University Xi’an 710072 China 

出 版 物：《Transactions of Nonferrous Metals Society of China》 (中国有色金属学报（英文版）)

年 卷 期：2016年第26卷第12期

页      面：3135-3146页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

基　　金：Project(51405392)supported by the National Natural Science Foundation of China Project(20136102120022)supported by the Research Fund for the Doctoral Program of Higher Education of China Project(3102015ZY023)supported by the Fundamental Research Funds for the Central Universities,China 

主　　题：laser beam welding titanium alloy dissimilar joint strain rate microstructure mechanical properties 

摘      要：The microstructure and mechanical properties of laser beam welded dissimilar joints in TC4 and TA15 titanium alloyswere investigated. The results showed that the coarse columnar grains containing a large amount of acicular α and martensite α′ werepresent in the fusion zone (FZ), some residual α phases and martensite structure were formed in the heat-affected zone (HAZ) onTC4 side, and bulk equiaxed α phase of the HAZ was on TA15 side. An asymmetrical microhardness profile across the dissimilarjoint was observed with the highest microhardness in the FZ and the lowest microhardness in TA15 BM. The orders of yield strengthand ultimate tensile strength were as follows: TC4 BM TC4/TC4 similar joint TA15 BM TA15/TA15 similar joint TC4/TA15dissimilar joint, and increased while hardening capacity and strain hardening exponent decreased with increasing strain rate from1×10?4 s?1 to 1×10?2 s?1. The TC4/TA15 dissimilar joints failed in the TA15 BM, and had characteristics of ductile fracture atdifferent strain rates.