Microstructural characterization of electron beam welded joints of TiAl-based in-termetallic compound

作     者：WU Huiqiang, FENG Jicai, HE Jingshan, ZHOU Li National Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, China 

出 版 物：《工程科学学报》 (Chinese Journal of Engineering)

年 卷 期：2005年第2期

页      面：221-221页

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] 

主　　题：electron beam welding titanium aluminide microstructure crack 

摘      要：The feasibility to use electron beam welding to join the nominal composition Ti-48Al-2Cr-2Nb alloy was assessed. The microstructure characterization and cracking susceptibility of the joints were evaluated by means of OM, SEM, XRD, and microhardness. It was found that the welded microstructure exhibited columnar and dendritic structures. Microstructural constituents in the fusion zone were a massive gamma structure and some amount of lamellar structure consisting of alternating platelets of α2 and γ. The major contributing factor to the susceptibility to solidification cracking was microsturctural change in this study for the suppression of α phase decomposition leading to produce more retained α2 brittle phase. Compared with transgranular cleavage fracture in the base metal, the weld metal exhibited mainly translamellar fracture.