Sturcture of Fe-30% Ni single crystals after the γ → α → γ transformation

X-ray diffraction examination of thin single-crystal plates of a pure carbon-free Fe-30% Ni alloy showed that martensite crystals with a preferred orientation appear after the γ → α, or transformation. The predominant orientation is governed by small thickness of the plates. An analysis of pole figures with account of the Kurdjumov-Sachs orientation relationship exhibits that the orientation with the smallest angle between the shear directions (1 1 1) α and (101) γ and the perpendicular to the surface of samples mainly occurs. Effects of heating rate in the reverse transformation on the recovery of the initial orientation and structure of austenite crystals were studied.