AUSTENITE STABILIZATION OF FE-NI ALLOY

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