A strategy to improve the work-hardening behavior of Ti-6Al-4V parts produced by additive manufacturing

To improve the mechanical properties of additively manufactured parts, specific heat treatments must be developed. Annealing of electron beam-melted Ti-6Al-4V was performed at sub-transus temperatures and followed by water quenching. Such treatments generate an alpha + alpha' dual-phase microstructure. Microstructural and mechanical characterizations revealed that the heat-treated specimens show a broad range of tensile properties, depending on the fraction of martensite. The specimens treated between 850 degrees C and 920 degrees C exhibit an increase in strength and ductility, which is related to a remarkable hardening behavior. Work-hardening is attributed to kinematic hardening arising from the mechanical contrast between the alpha and a alpha' phases.