AGING ENHANCEMENT IN WELD JOINT OF TI-15V-3CR-3SN-3AL ALLOY

Weld joint is locally deformed plastically and simultaneously restored at a high temperature after welding, and subsequently cooled to room temperature. Its singular thermomechanical hysteresis of the weld joint may affect aging behavior. Ti-15V-3Cr-3Sn-3Al alloys have showed aging enhancement in the weld joint. In the present study, we clarify the aging enhancement mechansim of this alloy on the base of the thermomechanical processing. A distinctive microstructure has existed in the weld joint after the welding and the subsequent cooling. Fringe-type microstructures of plate and bulk configuration may be created by local plastic deformation due to thermal stress after welding and by freezing of a solute atom atmosphere in the vicinity of edge dislocation component on cooling. Its distinctive microstructures have promoted the aging because of preferential sites for or precipitation. From the present results, a thermomechanical treatment has been proposed to obtain a high strength of this alloy by more short aging time.