The microstructural transformation and strength enhancement mechanisms in TiB/TA15 composite GTAW welded joints

This study focuses on the TiB/TA15 composite material and explores the optimal process parameters for its Gas Tungsten Arc Welding (GTAW). The material used is a 1.5-mm thick TiB/TA15 composite sheet. It is found that when the welding current is set at 65 A, the welding speed is maintained at 10 cm/min, and shielding gas is added to both the front and back sides of the weld during welding, the mechanical properties of the obtained welded joint are optimal. The welded joint is mainly composed of α’-Ti and TiB phases. During the welding process, TiB undergoes cracking and remelting. The average tensile strength of the welded joint reaches 862 MPa, which is close to 84.2% of that of the base material. The elongation after fracture is 5.8%. The fracture of the tensile specimen mainly occurs in the weld metal, and the fracture mechanism is cleavage fracture.