Investigation on the transformations in Ni2MnGa by capacitance dilatometry

Abstract

The present paper describes the use of high precision capacitance dilatometry to study the intermediate (pre-martensitic) transformation and the martensitic transformation in a Ni2MnGa single crystal. The results show that capacitance dilatometry is an effective method to study the phase transformations in Ni2MnGa. A significant discontinuity in the strain vs. temperature curves is observed around the martensitic transformation temperature. The thermal strain accompanying the martensitic transformation is not reproducible under the condition of no external constraint, and can be more reproducible with the application of external stress. The intermediate transformation is a weak, first-order ..