Research On Martensite Phase Transition And Its Crystallography

Study to modality of martensite, phase transition and analyse ofcrystallography has been carried for a long time, and its meaning is verygreat. M phase transition include abundant crystallography content. It iswith combining correct crystallography analyse that can make explanations to law of M phase transition of the certain form M. But the theory of M phase transition lag behind relatively now, or there is no corresponding experiment foundation.This paper does a research for typical form of lath form martensite and flaky martensite, inferior structure and characteristic it carries on in Fe-C alloy. During the observing of transmission electric microscope, we find that there is not the dislocation circle at the edge of lath martensite. But at the edge of portrait, we can see the dislocation knot. We confer that perhaps it is the state of transition of the FCC structure to the BCC structure, and the strain of shape of the bath martensite is concentrated at the direction of length. In the photos of transmission electric microscope , we can see both the twin crystal of phase change and deformation as inferior structure of the flaky M. As the twinborn shear department of {112}m is obstructed, slipping department {111}P of parent phase begin to work, rely on dislocation's slipping, coordinate flaky martensite's twinborn shearing and form dislocation inferior structure at M phase corresponding plane(contain the interface between parent phase and martensite phase). We do some calculation according to the difference abnormality, find that there are different matrix. According it, we can forecast the relation of martensite and parent phase. But it does not exceed the area of KS relationship. In the experiment of transmission electric microscope, find that accords with crystallography deriving generally.