Dual Characteristics of Tungsten Inert Gas–Brazing Hybrid Welded Joint of TC17 Titanium Alloy with Backing Plate

TC17 titanium alloy with backing plate is prepared by TIG and brazing hybrid welding method. Two kinds of weld metal with different properties are obtained, which is butt WM and brazed WM. The brazing material is reacted with the TC17 plate during welding process, and a small amount of brazing material is integrated into the butt joint. Optical microscopy and scanning electron microscopy are used to analyze the microstructure evolution of the welded joints. The microstructure of the butt weld area and brazing area is further characterized by X-ray diffraction and energy-dispersive spectrometery. The microstructure generation in the BA is intermetallic compounds with significant phase transformation. Dynamic recrystallization and elongated β-phase formation are occurred in the butt joint. The mechanical property is significantly improved by the intermetallic compound generated in the brazing area.