Pathways to Titanium Martensite

The structural relationship between the parent and product phases in martensitic transformation from ? phase is described. atomic movements leading to martensite are accomplished by a long-range shear {112} < 111 > that transforms lattice short-wavelength displacement or shuffle {110} 110 induces correct stacking. microstructures arising out of these paths depend on which modes initiates transformation. When precedes shuffle, conventional forms as dislocated laths internally twinned plates. A signature follows accompanies present both cases stacking fault-related domains. with increasing stabilizer addition, resulting nanodispersion structure orthorhombic symmetry, we have designated O?. Al, Sn, Zr O additions promote shuffle. O? dispersion acts embryos for formation nanomartensite cooling application stress. continuous controlled strain incorporation into within constrained nanoembryos results nonlinear superelasticity invar elinvar effects. stability bcc discussed terms phonon mode related elastic constant softening.