Microstructure evolution of friction welded dissimilar joint during subsequent hot work

Abstract

The present paper reports the influence of hot working conditions on the microstructure of Ti₂AlNb/TC11 dissimilar joint. Linear friction welding technique was used to fabricate the joints. The microhardness and tensile properties of the joints have been tested. It was found that the fine structure of linear friction welds underwent abnormal grain growth and abnormal grain boundary phase growth in the post-weld solution heat treated condition. This phenomenon significantly deteriorated the ductility of the joint. After appropriate hot work, abnormal big grains/phases disappeared, and the joint exhibited good tensile properties due to its fine structures.

Keywords:

• Linear friction welding
• Titanium aluminides
• Post-weld heat treatment
• Isothermal deformation

The research is sponsored by the National Natural Science Foundation of China (grant no. 50775187). The authors would like to thank T. J. Ma (NWPU, China) and J. W. Zhang (CISRI, China) for their warm assistance.