Yield of cyclic vs heat-and-hold induction sintering on the mechanical behaviour of the low-cost Ti-5Fe alloy

Abstract

The high cost of Ti alloys is hindering their industrial implementation and, therefore, the quest for low-cost Ti alloys entails lowering the intrinsic cost using cheaper alloying elements and developing more efficient manufacturing methods. In this study, the yield of manufacturing the novel low-cost Ti-5Fe alloy via heat-and-hold and cyclic induction sintering around the allotropic α→β phase transformation was compared as the latter is expected to enhance densification. It is demonstrated that induction sintering is extremely efficient due to its characteristic high heating rates and simultaneously permits to obtain homogenous chemical compositions at low homologous sintering temperatures. Cyclic sintering yields faster sintering kinetics, which results in higher densification with respect to heat-and-hold, achieving uniform residual porosity distributions within the microstructure, comparable relative density, and on average smaller and more spherical pores. Consequently, higher strength but not necessarily higher ductility is obtained for the cyclic sintered Ti-5Fe alloy as the failure mode entails crack propagation through irregularly shaped pores.