Mechanical Properties of Single-Melt PAM Processed Ti-6Al-4V Forgings

Abstract

Ti-6Al-4V pancakes were manufactured by alpha-beta forging using single-melt (SM) plasma arc melt (PAM) billet stock at three oxygen levels, 0.16, 0.20 and 0.24 wt%, along with a standard double vacuum arc remelted (2XVAR) billet stock at 0.17 wt% oxygen for baseline comparison. Mechanical properties of forgings in the mill-, recrystallization- and beta-annealed conditions were then characterized by microstructure examination, tensile, smooth bar axial fatigue and fracture toughness testing in radial orientation. The effect of oxygen content on mechanical properties of the forgings was assessed. All SM PAM forgings exhibited slightly higher tensile and fatigue strength compared to those of 2XVAR. The fracture toughness values decreased with increasing oxygen content. Microstructures of all forgings were similar to those of conventional alpha-beta forgings. The data presented in this paper can be useful to designers in their efforts to introduce low-cost SM PAM Ti-6Al-4V (Ti-6-4) alloy forgings into various U.S. defense applications.