On microstructure and property differences in a linear friction welded near-alpha titanium alloy joint

In this study, a near-alpha titanium alloy (Ti-6Al-2Zr-1Mo-1V) was welded with linear friction welding (LFW). The microstructural evolution and mechanical properties of the joint were evaluated. Results show that grains are remarkably refined in the weld center zone due to dynamic recrystallization because of the effect of thermo-mechanical coupling, while the fractions of deformation grains, sub-structure grains and recrystallized grains are significantly different from those of the base metal (BM). The room temperature tensile strength of the welded joint is not lower than that of the BM, because all the failure occurs in the BM. It is more interesting to find that the joint impact toughness is increased by 19.1% compared to the BM.