Reversible elastocaloric effect related to B2-R transformation in Ni50.5Ti49.5 alloy

In Ti-Ni alloys, the low hysteresis emanating from the B2 <-> R transition enables a fine control of reversibility in elastocaloric effects when there are lower values of applied stress. In this paper, we reported a Ni50.5Ti49.5 alloy synthesized by arc melting promoting the R phase. Using energy dispersive x-ray analysis, differential scanning calorimetry, x-ray diffraction, and elongation measures as a function of temperature, we have studied properties in an isolated R phase. We observe that there are similarities between the isothermal entropy change curves and the reversible adiabatic temperature changes, where a maximum value of reversible isothermal entropy of 14.6Jkg(-1)K(-1) at 310K is obtained when a stress of 222MPa is applied. We show that precipitates formed on the R phase play a role in the elastic behavior affecting the values of adiabatic temperature change.

Automated summary

This study focused on the properties of a Ni50.5Ti49.5 alloy with a promoted R phase, showing that it exhibits controllable elastocaloric effects and explores the variations in properties under different stress levels.