Phase stability and tensile behavior of metastable β Ti-V-Fe and Ti-V-Fe-Al alloys

The tensile property and deformation microstructure of a series of metastable beta Ti-V-Fe and Ti-V-Fe-Al alloys have been studied. The results show that although Al is an a-stabilizer element, Al addition suppresses the athermal to phase transformation in metastable beta Ti-V-Fe-Al alloys. The Ti-16V-Fe alloy plastically deforms via {332}< 113 > mechanical twinning and stress-induced omega phase with a special habit plane of {-5052}(omega)//{3-3-2}(beta), and the Ti-14V-2Fe-Al and Ti-12V-2Fe-Al alloys via {332}< 113 > twinning. The Ti-16V-2Fe, Ti-16V-2Fe-Al and Ti-16V-2Fe-2A1 alloys with relatively high beta phase stability plastically deforms mainly via dislocation glide. The Ti-16V-Fe, Ti-14V-2Fe-Al and Ti-12V-2Fe-Al alloys exhibit higher yield strength without loss of plasticity significantly than the binary beta Ti-V alloys deformed via {332}< 113 > twinning due to solid-solution strengthening effect of Fe and Al elements in the alloys.