Electron beam welding of a novel near α high temperature titanium alloy powder compact: effect of post-welding heat treatment on tensile properties

Abstract

A novel near α high temperature titanium alloy (Ti55) was produced from powder compact through hot isostatic pressing. Electron beam welding (EBW) was used to join the Ti55 alloy powder compact and effects of annealing treatment on the microstructure and mechanical properties of EBW joints were investigated. The residual stress distribution of as-welded joint was calculated using finite element method (FEM). The results show that the microstructure and microhardness profiles are non-uniform across the EBW joints. The tensile residual stresses are confirmed across the as-welded joints based on FEM analysis. All of tensile specimens failed at the base metal, indicating that the mechanical properties of EBW joints are equal to those of base metal, or better. The tensile strength of as-welded and as-annealed joints increases slightly compared with base metal. An obvious reduction on the reduction of area of EBW joints was obtained after annealing at 500 °C. Related mechanisms were discussed based on the residual stress, tensile deformation and the strain rate sensitivity.