Activated slip systems during yielding of α-β brass two-phase bicrystals

Abstract

α-β brass two-phase bicrystals, consisting of fcc (α) single crystals and bee (β) single crystals, which were made by the solid state diffusion couple technique, were tensile-tested at room temperature in order to clarify the role of phase-interface on the deformation. The two-phase bicrystals had small concentration gradients in theα- andβ-phases and satisfied the Kurjumov-Sach's orientation relationships i.e. {1 1 1} _α ∥ {1 1 0} _β and [1 1 0] _α ∥ [1 1 1] _β at the interface. The slip traces observed in bicrystals deformed to about 3% plastic strain showed a striking contrast between theα- andβ-phases; the slip traces in theα-phase were clear and straight, while those in theβ-phase were fine and wavy. The slip systems in the bicrystals were attributed to those observed inα andβ single crystals, and were explained by a plastic strain incompatibility mechanism. The slip systems, originating at the interface or propagating from another phase, were observed on matching planes.