First-principles study the structural phase transition, elastic and thermodynamic properties of HfCr 2

Abstract

Abstract We study the structural phase transition, elastic and thermodynamic properties of HfCr2 from first principles calculations. The simulated results are very close to those of previous studies. The phase transition from C15 to C36 occurs at about 202.7 GPa, while the phase transition pressure from C36 to C14 is about 283.9 GPa. It can be seen from the phonon spectra and elastic constants that HfCr2 is mechanically stable at C15 phase. It can be concluded that C15 phase HfCr2 is ductile from 0 to 200 GPa, and the bigger the pressure, the greater the ductility from G/B value and Poisson's ratio. Then, through the analysis of density of states, the mechanism of metal properties is discussed. Finally, the relation of thermal expansion coefficient, Debye temperature and thermal capacity to pressure and temperature are discussed.