Effect of Aging On Martensitic Transformation Behavior of Ti48.8Ni50.8V0.4 Alloy

It is generally accepted that alloying is the most effective method to control the transformation temperature of TiNi-based shape memory alloys. The proper addition of vanadium (V) can remarkably lower the transformation temperature, hence favors stable superelasticity at room temperature. Previous reports on TiNiV alloy focused on the fundamental aspects, including precipitation behavior, martensitic transformation and shape memory effect. However, further report on the effect of aging on superelasticity of TiNiV alloy is yet not available. In this paper, the effect of aging on superelasticity of Ti_48.8Ni_50.8V_0.4 alloy was investigated by tensile testing at different temperatures. The aged Ti_48.8Ni_50.8V_0.4 alloys show a well defined superelastic shape recovery. During cycling deformation with strain increment, the recovery strain and stress hysteresis both increase. When the samples were aged for 30 min, the critical stress to induce martensitic transformation decreases with the increasing of aging temperature from 300 to 500 °C. Further increasing in the aging temperature results in the increase of critical stress to induce martensitic transformation. When the samples were aged at 500 °C, the increasing of aging duration leads to the decrease of recovery strain and the critical stress to induce martensitic transformation.