Abstract
Characteristic properties of phase transition particles such as martensitic transformation, order-disorder transition in fine particles of Fe-Ni alloy were discussed in correlation with particle size. The mechanisms of γ-α phase transition of ferric oxide were also suggested from the electron diffraction studies of particles.
In genaral, diffusionless martensitic transformation, is suppresed with the decreasing of particle size. This effect is explained by the decrease of dislocarion density in fine particles. Meanwhile order-disorder transformation which accompanies diffusion is promoted by the excess vacancies introduced by the surface tension effect.
Lastly shape and size effects in the transformation of γ-ferric oxide were desccribed.
