Abstract
Dynamic deformation behaviors in tensile experiments of austenitic stainless steel SUS304 under strain rate of 6.7×10^<-5> s^<-1> were investigated by dynamic electronic speckle pattern interferometry (DESPI). In the method, contour maps of an in-plane component of deformation can be sequentially displayed as an animation of speckle correlation patterns. In a later process of the plastic deformation state, X-shaped localized deformation bands which ran over the specimen, were observed. Correspondingly, projection-like variation appeared on the stress-strain curve. In order to investigate the phenomena related to strain induced martensitic transformation (SIMT), changes of magnetic properties of the materials were also measured using FERRITESCOPE. A two-dimensional map of permeability coincided with a deformation contour obtained by DESPI. We concluded that the X-shaped localized deformation band running over the specimen is the front of SIMT.
