Extended application of edge-to-edge matching model to HCP/HCP (α-Mg/MgZn2) system in magnesium alloys

In the present work, the edge-to-edge matching model has been introduced to predict the orientation relationships (OR) between the MgZn2 phase which has hexagonal close packed (HCP) structure and the HCP α-Mg matrix. Based on the crystal structures and lattice parameters only, the model has predicted the two most preferred ORs and they are: (1) [1 1 2¯ 3]α-Mg||[1 1 2¯ 3]MgZn2,(0 0 0 1)α-Mg 0.27° from (0 0 0 1)MgZn2,(1 0 1¯ 1)α-Mg 26.18° from (1 1 2¯ 2)MgZn2, (2) [1 0 1¯ 0]α-Mg||[1 1 2¯ 0]MgZn2,(0 0 0 1)α-Mg||(0 0 0 1)MgZn2,(1 0 1¯ 1)α-Mg 3.28° from (1 1 2¯ 2)MgZn2. Four experimental ORs have been reported in the α-Mg/MgZn2 system, and the most frequently reported one is ideally the OR (2). The other three experimental ORs are near versions of the OR (2). The habit plane of the OR (2) has been predicted and it agrees well with the experimental results.