Annealing twin interfaces in an austenitic stainless steel

Abstract

Abstract Planar first and second-order twin interfaces in an austenitic stainless steel have been examined by transmission electron microscopy. Two types of planar non-coherent first-order twin interfaces are possible, one of which is parallel to the {5, 5, 13} planes which are parallel to {7, 7, 11} planes in the twin. The other type of interface is parallel to the {110} planes which are parallel to planes of similar indices in the twin. Second-order twin interfaces were frequently observed to be planar on a macroscopic scale and parallel to {111} planes in one grain and {115} planes in the twin. Small grains in a first-order twin relationship to the other two grains were always present at these interfaces. These twins were bounded by two interfaces parallel to the two twinning planes and a non-coherent interface of the type described above. The structure of these interfaces is discussed in terms of the coincidence lattice theory of twinning.