Nanometre-sized ! '-martensites , a few nanometres in cross-sectional diameter, formed at intersections of deformation twins, have been found in a heavily deformed 316-type austenitic stainless steel and examined by high-resolution transmission electron microscopy . An orientation relationship was found to be close to the Kurdjumov-Sachs relationship, that is , . HRTEM observations were conducted with a beam direction parallel to . The observed nanometre-sized ! '-martensites exhibited a habit plane and the cross-section of the nanometre-sized ! '-martensites were elongated (...) along [545] % . It has been revealed that the nanometre-sized ! '-martensites of a few nanometres diameter formed at the intersections of deformation twins have a typical habit plane of , which is identical with that reported for a fully grown plate such as ! '-martensite. The origin of the observed habit plane is discussed on the basis of the d 112 ¢ {111} ! shear displacements assisting the % M ! ' transformation. (shrink)