Substructures in deformed Fe-15 Ni-0.8 C austenite
In a recent study, the mechanical behavior of an Fe-15 Ni-0.8 C austenite was determined at various strain rates and temperatures. An important finding of this study was the formation of intense shear bands during deformation at temperatures much greater than which bore no resemblance to the common morphologies of martensites. There is much disagreement in the literature regarding the mechanism of band formation and the associated substructure. These bands have been reported to be fine BCC martensite particles or laths delineating slip bands or thin twins in the austenite matrix. The purpose of the present work was to determine by transmission electron microscopy and diffraction the substructure of the fine bands and to attempt to clarify the various interpretations. For comparison, the substructure produced at a lower deformation temperature was also evaluated where the martensite was known to have the normal strain-induced morphology.