Microstructure and residual stress distribution of electron beam-welded joints of a 50 mm-thick TA15 titanium alloy plate

Abstract Vacuum electron beam welding was applied to a 50 mm-thick TA15 titanium alloy plate. Microstructure observation and microhardness testing were performed. Meanwhile, the residual stress on the surface at different distances from the weld centre was measured via the hole drilling method. A finite element model for electron beam welding of the TA15 titanium alloy plate was constructed on commercial finite element software. Experimental results showed that the microstructure of the weld zone consisted of a basket martensitic phase. The highest microhardness in the weld zone was 409 HV, and the microhardness of the base metal was the lowest. The maximum gradient change area was located at the HAZ near the base metal. The peak value of longitudinal residual stress from the simulation was 880 MPa, which was in the weld metal. The sharp change area of longitudinal residual stress gradient was located in the base metal near HAZ.