Quench- and deformation-induced structures in two austenitic stainless steels

Abstract

Composite electron-diffraction patterns have been computed and used to facilitate the interpretation of experimentally determined patterns obtained from the structures and phases observed by transmission electron microscopy in two quenched and/or deformed unstabilized austenitic stainless steels. The results of these studies, together with data obtained from magnetic measurements and X-ray diffraction analyses, have demonstrated that deformation twins, stacking-fault bundles (or faulted ɛ-martensite) and α′-martensite are produced in the austenite matrix of an AISI Type 301 (18Cr–8Ni) steel after quenching and/or cold rolling, whereas only deformation twins are formed during the cold rolling of an AISI Type 316 (17Cr–13·5Ni–2·4Mo) steel. The results and observations have enabled some of the uncertainties in the literature regarding the formation of the ɛ- and α′-martensites and their orientation relationships with the parent austenite to be clarified.