The effect of stacking fault energy on the formation of stress-induced internally faulted martensite plates

摘要

Stress-induced martensitic transformations proceeding by the formation of internally faulted martensite plates are studied. The additional free energy associated with random stacking faults and the distinct elastic anisotropy of parent and product phases are accounted for in the micromechanical analysis of a thin plate-like inclusion of the martensite in the austenite matrix. The microstructure of the martensite plate is obtained as a solution of a constrained minimisation problem for load multiplier. The stress at which the transformation initiates and the predicted microstructure, i.e., plate orientation and the magnitude of shear induced by the stacking faults, depend on the stacking fault energy, loading direction and temperature. As an example, the microstructures are analysed in the 6M (M18R) martensite of a CuZnAl shape memory alloy.