THE INFLUENCE ON MICROSTRUCTURE AND MECHANICAL PROPERTY OF ELECTRON BEAM WELDED JOINT TC4 ALLOY WITH DIFFERENT HEAT TREATMENT

The TC4 titanium alloy was welded by electron beam (EBW),after that,the samples have been annealed and solution treated pre-welded separately. Microstructure and phase composition characteristics of base metal,heat affected zone (HAZ) and fusion zone (FZ) of these welds of TC4 were studied by means of OM and XRD. Tension and impact test were carried out at room temperature. The results indicated that EBW TC4 welds with different pre-and post-weld heat treatments have different microstructures in base metal,HAZ and FZ,which result in the ultimate tensile strength (UTS) and yield strength (YS) of annealed state welds less than that of solution treated welds,but the impact toughness of the former greater than the latter. However,the UTS,YS and impact toughness of the two kinds of welds larger than that of base metal.