Cryston model of formation of α strain induced martensite

Abstract

The strain-induced martensite formation is considered as a consequence of carry of a threshold plastic deformation by crystons. The sources of crystons (carriers of shear of a superdislocation type) are caused by interaction of dislocations belonging to systems with intersected slip planes. For crystons (carriers of simple shear) the physical nature of morphological features of a strain-induced martensite crystals and their difference from a case of stress-induced and cooling-induced martensites is discussed. A case of crystal with habits of {hhl} - type is analyzed most explicitly. The deformations of compression ε2 and tension ε1 along orthogonal axes <001> initiating the Bein strain process are considered as order parameters controlling the austenite stability. The connection between the abnormal orientation relationship for α′ martensite crystals formed under tensile loading and the threshold deformation is obtained.