Stress induced transformation: In between Ms & Ms sigma this transformation is active. Above Ms temperature stress required for transformation is increasing (free energy is decreasing) & at the same time parent austenite stress is decreasing. Where this two are met, that is called Ms sigma temperature (stress required for transformation & parent austenite stress decreasing). Below Ms sigma temperature stress induced transformation occurs, marteniste nucleate on pre-existing defects in austenite.

Strain induced transformation: Above Ms sigma temperature material is strained, here martensite nucleate on new generated defects such as SFE, shear bands, micro bands, dislocation interactions.

Stress induced transformation occurs in between Ms and Ms sigma temperature.

Thank you for your comment!

When the martensitic transformation occurs at a stress level lower than the YS, it cannot be called strain-induced martensite.

So, is those martensite transformation under YS stress-induced martensite transformation?

When I saw some paper, the mechanism between stress- and strain- is different.

At temperatures near Ms, the stress required for slip in the austenitic matrix exceeds that necessary for the martensitic transformation. Conversely, as the temperature increases toward the Md temperature, the stress required for martensite formation increases to a level above that required for slip in the austenite.

Martensite is considered to be "stress-induced" when it forms as a result of elastic stresses from an external load (i.e., below the yield strength of the austenite). Martensite is "strain-induced" when slip in the austenite precedes its formation.

Do you know what is the difference between stress and strain induced martensite ? In my study, I found the change of these two manners during deformation. While I can't distinguish it from other in TEM.