Influence of slip and twinning on the crystallographic stability of bimetal interfaces in nanocomposites under deformation

In this work, we examine the microstructural development of a bimetal multilayered composite over a broad range of individual layer thicknesses h from microns to nanometers during deformation. We observe two microstructural transitions, one at the submicron scale and another at the nanoscale. Remarkably, each transition is associated with the development of a preferred interface character. We show that the characteristics of these prevailing interfaces are strongly influenced by whether the adjoining crystals are deforming by slip only or by slip and twinning. We present a generalized theory that suggests that, in spite of their different origins, the crystallographic stability of their interface character with respect to deformation depends on the same few basic variables.