Effect of Ultrasonic Impact on the Microstructure of Welded Joint of 2195 Al–Li Alloy

作     者：Qi-Hao Chen San-Bao Lin Chun-Li Yang Cheng-Lei Fan 

作者机构：State Key Laboratory of Advanced Welding and JoiningHarbin Institute of Technology 

出 版 物：《Acta Metallurgica Sinica(English Letters)》 (金属学报（英文版）)

年 卷 期：2016年第29卷第4期

页      面：367-372页

核心收录：

学科分类：080503[工学-材料加工工程] 0817[工学-化学工程与技术] 0806[工学-冶金工程] 08[工学] 0807[工学-动力工程及工程热物理] 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] 0703[理学-化学] 0811[工学-控制科学与工程] 080201[工学-机械制造及其自动化] 

基　　金：supported by the Key Program of the National Natural Science Foundation of China(Grant No.51435004) 

主　　题：Ultrasound TIG welding Microstructure Al-Li alloy 

摘      要：It is known that an ultrasonic impact during tungsten inert gas welding can refine the grains and improve the mechanical properties of the welded joints of aluminum alloys. However, the influence mechanism of the ultrasonic impact on the microstructures is still unclear. In this research, the effects of the mechanical and ultrasonic impact on the microstructures of the welded joint of 2195 Al-Li alloy are analyzed. It is found that the mechanical impact could not refine the grains, but the ultrasonic impact could refine the grains. The grains become smaller in the weld center with an increase in the ultrasonic amplitude. Possible mechanisms for the grain refinement are discussed. The results show that the small temperature gradient promotes formation of the equiaxed grain and the cavitation promotes heterogeneous nucleation.