Morphologies and characteristics of deformation induced martensite during tensile deformation of 304 LN stainless steel

The austenite gamma (fcc) matrix of 304 LN stainless steel transforms readily to martensites epsilon (hcp) and alpha' (bcc) on deformation. The formation and nucleation mechanism of deformation induced martensite (DIM) during tensile deformation of 304 LN stainless steel has been studied at various strain rates in room temperature. It is investigated that the enhancement of strain rates during tensile deformation promotes the early formation of DIM, while suppressing its saturation value at fracture. Extensive transmission electron microscopy (TEM) studies showed more than one nucleation site for martensite transformation and the transformation mechanisms were observed to be gamma (fcc) -> epsilon (hcp), gamma (fcc) -> alpha' (bcc) and gamma (fcc) -> epsilon (hcp) -> alpha' (bcc). (c) 2007 Elsevier B.V. All rights reserved.