Electron-phonon coupling mechanism of premartensitic transformation in Ni2MnGa alloy

The driving force of premartensitic transformation (PT) based on the electron-transverse acoustic (TA) phonon interaction Hamiltonian was first calculated. The driving force of Ni2MnGa alloy is about 172.2meV, larger than that of NiTi-Fe or Ni-Al alloy. The nucleation rate of PT has also been investigated in the interaction system. Considering the electron-phonon interaction and the condensation of TA phonon, double sine-Gordon equation of atomic phase angle has been proposed to study the nonlinear characteristics of PT and the electron-TA phonon coupling mechanism may be taken as its main mechanism. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.