Thermoelastic intermartensitic transformation and its internal stress dependency in Ni52Mn24Ga24 single crystals -: art. no. 052411

We have found a perfect thermoelastic intermartensitic transformation between the seven-layer modulation (7M) and the five-layer modulation (5M) martensites in an unstressed Ni52Mn24Ga24 single crystal. In particular, we found that the intermartensitic transformation is very sensitive to the internal stress built up during the grinding process. Based on our calculation, an average internal stress of 13.8+/-1.08 MPa stored in the distorted lattice will force the parent phase to take a totally different martensitic transformation path during cooling and results in the entire suppression of the intermartensitic transformation. These results can be interpreted in terms of the formation of a 5M martensite which is facilitated by the elastic deformation.