Welding Characteristics of Titanium Alloy Joints Welded by Hollow Cathode Vacuum Arc Welding

Abstract:

The microstructure of Ti-6Al-4V joints by hollow cathode vacuum arc welding with different gas flow rates was studied, and the tensile properties were investigated. The results show that the microstructure of base metal is a mixture of α phase and β phase. The microstructure of heat affected zone are equiaxed and primary α phase and needle martensite α′ phase dispersed in the transformed β phase. The distribution of two kinds of microstructures in the heat-affected area is affected by the welding thermal cycle. The microstructure of weld seam mainly consists of α′ martensite phase. The decrease in welding gas flow rate and the increase in welding energy density result in coarse and more scattered martensitic grains. The tensile strength of welded joint is higher than that of base metal.