The characteristics of
γ→
ε transformation and stacking faults in the sub-stability Fe-12Cr-10Mn(W,V) alloy (84) after solution-treated followed by cooling in air and by quenching into ice water and these in the phase stability Fe-13Cr-17Mn(W,V) alloy (85N) after solution-treated followed by water, solution-treated followed by deformation were investigated by transmission electron microscope (TEM) and X-ray diffraction. Some ways to increase the phase stability were also carried out through analyzing the influence of some elements on the transformation of
γ→
ε.