抄録
Deformation induced martensitic transformation in spherical iron particles has been studied in a Cu-1 wt%Fe alloy single crystal. The structural change on deformation and the dependence of the fraction of the martenstic transformation of the particles on the particle size have shown that transformation in an iron particle initiates when a glide dislocation meets a particle. Dislocation stress aids the {111}f⟨211⟩f lattice shear involved in the lattice change of γ to α. Change of the banded structure of the α iron particles on annealing has been examined. At the early stage of annealing, the particle shape becomes angular and the number of the twin bands abruptly decreases. It has been suggested that de-twinning of a band takes place, resulting in coalescence of neighbouring bands and at the same time the diffusion of copper atoms occurs. At the later stage, the particle shape becomes smooth and elongated. The axis of the elongated particles is parallel to the [110]f and [\bar111]b, which coincide with the directions of the preferentially formed martensite particles on deformation.
