Study on microstructure and mechanical properties of ring welding seam in TA16 titanium alloy tube

Abstract

The microstructure, grain boundary characterization and crystal orientation of ring welding seam in TA16 titanium alloy tubes have been analyzed by means of EBSD technique. The results show that the microstructure of base metal is composed of fine equiaxial α-grains with large angle grain boundaries and fiber texture. Due to effect of heat cycle, microstructure varies along with distance from welding seam which has increased small angle grain boundaries but lower than large angle grain boundaries in HAZ. The texture here inherits base metal texture characteristic with lower density. It appears the basket structure composed by α’-martensite with high dislocation density distribution and desultory texture in the melting zone. The tensile strength and hardness at HAZ and melting zone are higher than base metal.