Austenite Stabilization of Fe-Ni Alloy

By X-ray powder diffraction and magnetometric methods we investigated the effect of phase hardening during γ-α-γ transitions. In this case austenite becomes more stable to subsequent γ-α-γ transitions, the dislocation density increases, the grain reduce in fragments and the hardness increases, too. In addition the γ-solid solution in some steels is unstable during ageing. The phase hardening was found to stabilize the γ-solid solution of Fe-Ni alloy to subsequent thermal treatment. This is consistent with an increase in carbon mobility after γ-α-γ transitions. That is why decarbonizations of austenite take place during increase in extent of phase hardening.