Interfacial structure and crystallographic studies of transformations in βt [formula omitted]and β CuZn alloys—II. martensitic formation of α1′ plates in β′

Abstract

A TEM study of the interphase boundary structure of 9R orthorhombic α 1' martensite formed in β′ CuZn alloys shows that it consists of a single array of dislocations with Burgers vector parallel to 〈110〉 β′ and spaced about 3.5 nm apart. This Burgers vector lies out of the interface plane; hence the interface dislocations are glissile. Unexpectedly, though, the Burgers vectors of these dislocations are not parallel when referenced to the matrix and the martensite lattices. This finding is rationalized on published hard sphere models as a consequence of relaxation of a resultant of the Bain strain and lattice invariant shear displacements within the matrix phase.