The atomic structure of the interphase boundary which enclosed an hexagonal close-packed  precipitate that formed from a body-centered cubic  matrix was studied. All of the interfaces of an  lath exhibited a continuity of the atomic planes between the matrix and the precipitate, and were therefore considered to be coherent or semi-coherent. The observations implied that there was an atomic site correspondence during transformation. The shear component of the transformation strains which arose from the passage of (a/12)[111] transformation dislocations (structural ledges) on (112)||(11•0) planes was accommodated by a set of glissile dislocation loops which existed on every sixth (11•0) plane at the side facet and the edge of an  lath. The volumetric component of the transformation strain was accommodated by a set of sessile misfit dislocations, b = (a/2)[110] = (c/2)[00•1], on the risers of the growth ledges at the side facet. The presence of sessile dislocations implied that the migration of / interfaces was a non-conservative process and should accompany the diffusion of substitutional atoms.

T.Furuhara, T.Ogawa, T.Maki: Philosophical Magazine Letters, 1995, 72[3], 175-83