Effect of twins on the crystallographic characteristics of the Mg17Al12 phase in the pre-compressed AZ91 alloy.

Crystallographic characteristics of the β-Mg 17 Al 12 phase have been investigated in the pre-compressed and aged Mg-9.0 wt%Al-1.0 wt%Zn alloy. Due to pre-compression, morphologies of the β phases became much wider and shorter. The aspect ratio was reduced dramatically. Besides, octahedron shaped β phase with Crawley OR have been observed and portion of the β phase with Crawley OR increased. The twins generated by compression affect the ORs of the β phase. The OR between the β particle and the {1 0 −1 2} twin is: [1 −2 1 0] α //[1 1 −1] β , (0 0 0 2) α near parallel to (1 −2 −1) β . ORs between β particles and the {1 0 −1 1} twin were more complex. Two typical ORs between the β particles and the {1 0 −1 1} twin have been identified as: [1 −2 1 −3] T //[1 1 0] β1 , (1 −1 0 1) T //(3 −3 0) β1 and [1 −2 1 −3] T //[1 1 3] β2 , (0 −1 1 1) T //(2 1 −1) β2, which have rarely been reported before. [ABSTRACT FROM AUTHOR]