Balance of strength and ductility for laser directed energy deposited Ta-containing Ti6Al4V via solution and aging treatment

Abstract

The tensile properties of laser directed energy deposited (LDEDed) titanium (Ti) alloys are usually characterized by high strength and low ductility, which seriously limits their wide application prospects. In this study, a novel Ti6Al4V4Ta alloy is prepared using LDED technique and achieved excellent strength (UTS ~ 990 MPa) and ductility (elongation ~ 16 %) through solution treatment at 930 ℃ and aging at 550 ℃. The high strength is mainly attributed to the ultrafine micron-scale αs while the good ductility results from equiaxed αp, the increased β phase and weakened α-variant selection. The combination of appropriate elemental alloying and heat treatments could provide some guidance for LDED Ti alloys of good mechanical performance with potentials for wider applications.