Explanation

According to the growth mechanism of new phase, a kind of structural transformation can be divided into shear phase transformation and non shear phase transformation. Its common feature is that the growth of new phase is not formed by atomic diffusion (that is, the disordered atomic beating unrelated to each other), but by collective and regular row transfer. The diffusionless transformation has the following characteristics: atoms keep one-to-one correspondence during the phase transformation, if the parent phase is an ordered phase, the generated phase is also an ordered phase; The chemical composition of the parent phase is the same as that of the generated phase; transformation is accompanied by shear deformation; There are habitual faces, represented by the face indices in the parent phase, most of which are irrational number indices (shear forms); There is a orientation relationship between the old and new phase; Shear type substructure and crystal defect appear in the new phase.

Classification