On the study of the f.c.c.-h.c.p. martensitic transformation using a diffraction approach-I. F.c.c. → h.c.p. transformation

Abstract

A new approach based on diffraction evidence for the involvement of shear at the atomic level is proposed to elucidate the mechanism of the f.c.c. to h.c.p. martensitic transformation. This approach is based on the analysis of the intensity distribution along streaked reciprocal lattice rows observed on diffraction patterns recorded from partially transformed f.c.c. crystals. The relevant theory of diffraction from crystals undergoing f.c.c.-h.c.p. transformation by non-random insertion of deformation faults is developed. This approach, as distinct from the conventional microstructural approach, can be especially useful in situations where the transformation strains are self accommodating in nature, such that there is no observable surface relief effect.