Mechanically induced martensitic transformation as a stress-driven process

Combined shear-tension tests at room temperature performed on a 12Cr9Ni4Mo low carbon austenitic stainless steel have been reviewed and evaluated under the assumption that the martensitic transformation is exclusively stress driven. It is shown that the start of the transformation is very well predicted using a criterion which involves only the mechanical driving force due to the acting stress. A very simple expression for a so-called transformation yield surface is obtained. Also, the kinetics due to different strain paths coincide when the transformation is evaluated as function of the mechanical driving force.