Model for the elastic behavior near intermartensitic transitions

Transitions between different martensitic states have been observed in Ni 0.50 Mn 0.284 Ga 0.216 using elastic constant measurements. In this paper, we develop a model to explain the reentrant behavior based on a Landau expansion of the free energy in strain space. Here, we assume that the coefficient of the third-order term as well as the second-order term has significant temperature dependence. This assumption results in a C ′ versus temperature in good agreement with observation. The model and possible modifications to it are discussed and compared to the elastic constant data.