Experimental study on crystallography of martensitic transformation
摘要
The more precise crystallography of martensitic transformation, including the conventional features of (3 15 10)f martensite, composition morphology and deformation details during the transformation, has been determined by a new metallography method and improved TEM technique as well. The determined results are in agreement with the shear-rotation crystallography theory. It is found that the martensite formation of polyvariant composition is attributed to the self-accommodation of the shape strains of the individual variants. However, the variant composition in 'kink' morphology results from cross-gliding of the martensite lattice deformation along {111}f planes. The lenticular martensite with (295) f habit is found to form through stacking up with subplatelets along the (111) f shear plane of the lattice deformation relevant to it. The present work, therefore, gives a new understanding of the midrib and (011)b twin or (011)b plane defects observed in the lenticular martensite.