Comparison of fatigue performance of TC4 titanium alloy welded by electron beam welding and laser welding with filler wire

This research compared high-cycle fatigue (HCF) performances of joints of Ti-6Al-4V titanium (TC4) alloy with the thickness of 30 mm welded by vacuum electron beam welding (EBW) and laser welding with filler wire (LWFW) (hereinafter referred to as EBW and LWFW joints). Under test conditions, the fatigue strength of the LWFW joint is only 65% that of the EBW joint. Based on analysis, the main reason is that a larger microhardness gradient is present in the LWFW joint. The average microhardness of the weld metal (WM) of the LWFW joint is 41 HV lower than that of base metal (BM). A lot of punctate beta phases in the WM of the LWFW joint may be an important reason for its softening. The research results provide data supports for the application of the EBW and LWFW of Ti alloy in the field of aviation manufacturing.

Automated summary

This research compared the high-cycle fatigue (HCF) performances of Ti-6Al-4V titanium alloy joints with a thickness of 30 mm, welded using vacuum electron beam welding (EBW) and laser welding with filler wire (LWFW). The fatigue strength of the LWFW joint was found to be only 65% that of the EBW joint. Analysis revealed that a larger microhardness gradient in the LWFW joint was the main reason for this difference, with the average microhardness of the weld metal (WM) in the LWFW joint being 41 HV lower than that of the base metal (BM). The presence of punctate beta phases in the WM of the LWFW joint could be an important factor contributing to its softening. These research findings provide data supporting the application of EBW and LWFW of Ti alloy in aviation manufacturing.