Written by mfm304:
Austenite in stainless steel is meta-stable. So, when it deformed, it transforms to the more stable phase, martensite. This transformation is a function of temperature and degree of deformation.
The stability of the austenite is expressed as the temperature at which 30% deformation (uniaxial tension) produces 50% transformation.
It is related to composition in the following way:
Any alloy addition lowers the Md30 and stabilizes the austenite.