Effect of uniform distribution of α phase on mechanical, shape memory and pseudoelastic properties of Ti–6Cr–3Sn alloy

Recently, among our developed Ti–Cr–3Sn alloys, the Ti–6Cr–3Sn alloy exhibited good mechanical, shape memory and pseudoelastic properties. However, the shape memory effect was incomplete, the pseudoelastic recovered strain was small and the ultimate tensile strength (UTS) was low. Therefore, in this study, the effect of a step heat treatment at 973 K (SHT973K) in the (α + β) region with the purpose of creating a uniform distribution of the α phase in the β phase matrix using ω phase precursors was investigated. It was determined that the step heat treatment in the 973 K (α + β) region was effective for improving the strength, shape memory and pseudoelastic properties of the Ti–6Cr–3Sn alloy due to the uniform distribution of the α phase in the β phase matrix, which resulted in a more effective increase in the critical stress for slip deformation. It is concluded that the uniform distribution of the α phase in the β matrix is an excellent method for improving the mechanical, shape memory and pseudoelastic properties of ω-sensitive β Ti alloys.

► Step heat treatment at 973 K (SHT973K) has resulted in uniform distribution of α phase in β matrix of β Ti alloy.
► Uniform precipitation of α phase was due to ω phase precursors.
► Yield stress, UTS, shape memory and pseudoelastic properties were improved by SHT973K.
► Non-linear strain recovery increased and permanent deformation decreased by SHT973K.