Study On Mechanism Of Martensitic Transformation

D model is a kind of martensite nucleation model. It considers that invariant plane strain control the nucleation process; 106 atoms join in the process and move collectively and regularly; it is a illegibility graded bedding, not a clear interface between martensite and parent phase; in the graded bedding which includes a few hundred atoms, the strain is invariant plane strain; the martensites appear on the invariable plane of the invariant plane strain; the invariant plane strain can be diluted, so can reduce elastic energy and nucleation energy barrier.A new model is putted forward on the basis of D model. It considers that the Y dipoles which result in martensitic transformation appear at the special place of dislocation stress field, so the nucleators of martensite firstly appear nearby the dislocation; after the first martensites nucleated, elastic energy reserved in the austenite is released, so elastic wave of the Y dipole spread in the crystals. When it is transformation temperature, elastomeric stamp is softened, and the resilience of the elastomeric stamp is zero, so that elastic instability is arosed in the parent phase. The elastic wave is coupled with the lattice vibration of parent phase in the transmission process, so soft mode is strengthed , and successor martensite nucleator is formed easily.