Crystallography of Mg2Sn precipitates with two newly observed orientation relationships in an Mg-Sn-Mn alloy

Two new orientation relationships between beta-Mg2Sn precipitates and alpha-Mg matrix have been observed by transmission electron microscopy. One is (1 1 0)(beta)//(0 0 0 1)(alpha), [0 0 1](beta)//[1 - 1 0 0](alpha), and the other is (1 1 0)(beta)//(0 0 0 1)(alpha), [-1 1 -1](beta)//[1 1 0 0](alpha). The precipitates with both orientation relationships exhibit a lath shaped morphology, with the long axis lying along [1 1 - 2 0](alpha). The morphology is interpreted by a three-dimensional near coincidence sites model.