A LARGE AMPLITUDE LATTICE DYNAMICS MODEL OF THE THREE DIMENSIONAL CRYSTAL DISPLACIVE PHASE TRANSITIONS
Cuj Naiyi ( Department of Fundamental Sciences )
A theoritical method dealing with the nucleation processes in the displacive transitions of metals has been raised. The phonons in crystals are classified into two kinds: common phonons and large amplitude phonons.The latter lead to lattice instability and transition. The transition displacive fluctuations can only take several wave vector directions and there are several shear directions corresponding to the wave vectors The equations satisfied by displacing fluctuation wave vectors and shear directions are presented.