Published online by Cambridge University Press: 15 February 2011
A mechanistic model of the nucleation and growth of martensitic products that is consistent with the phenomenological theory of martensite crystallography is described, and applied to the case of NiTi. In addition to the lattice invariant deformation specified in the phenomenological theory, an array of interfacial transformation dislocations, or disconnections, is present. The motion of these disconnections across the interface between the nucleus and matrix cause the growth of the precipitate, and the two defect arrays in combination relieve the strain in the nucleus. For such processes to be diffusionless, special crystallographic circumstances must arise, and these are explored in the paper.