Characterization of the matrix-twin interface of a (10(1)over-bar2) twin during growth
A Ostapovets and A Serra, PHILOSOPHICAL MAGAZINE, 94, 2827-2839 (2014).
A model of twin growth in magnesium is presented together with the analysis of defects responsible for this growth. The twin interface is represented by 10 (1) over bar2 and basal-prismatic facets. Disclinations are situated in the facet junctions creating dipoles superimposed on basal-prismatic and conjugate twin facets. The migration of facets is mediated by the conservative motion of interfacial disconnections. The 10 (1) over bar2 interfaces contain b(2/2) twinning disconnections. The facet junctions serve as sources and sinks for these defects. Two types of disconnections (b(1/1)(bp) and b(2/2)(bp)) were observed in basal-prismatic boundary. The dipoles of b(2/2)(bp) disconnections were nucleated in the vicinity of existing defects of this type. Interaction of this dipole with existing b(1/1)(bp) leads to the creation of a b(2/2)(bp) disconnection, which is later absorbed in the facet junction. The nucleation of b(2/2)(bp) dipoles was not observed. In twin embryo growth, the basal-prismatic segments remain coherent with a fixed length, while the twin segments grow indefinitely.
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