Additive manufacturing of a nanocrystalline lathy Ti6Al4V5Cu alloy with high strength and ductility combination

Among various types of microstructures in titanium alloys, martensitic microstructure has the highest strength, but with poor ductility, which restricts its applications in the engineering practice. In this study, we have efficiently refined the martensite lath width from 500-1000 nm to 50–200 nm through 5% copper alloying in the Ti6Al4V alloy through laser powder bed fusion. The strength of the material increased from 1090 MPa of Ti6Al4V to 1460 MPa of Ti6Al4V5Cu with the elongation of 11.2%. The nanocrystalline lathy Ti6Al4V5Cu alloy prepared in this study can provide reference for the material design of new ultra-high strength titanium alloys.