BIAXIAL PATH DEPENDENCE OF DEFORMATION SUBSTRUCTURE OF TYPE-304 STAINLESS-STEEL

Although martensitic transformations in austenitic stainless steels have been studied thoroughly for uniaxial monotonic and cyclic loading, data are scant for biaxially loaded specimens. In particular, recent nonproportional straining experiments have indicated a significant increase in cyclic hardening beyond that observed in uniaxial tests at equivalent strain levels. In this paper, a link is made between the additional hardening and microstructural uniformity of the transformation product. This link is expressed through a micromechanical viewpoint via increased latent hardening associated with rotation of the principal stress and plastic strain rate directions.