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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]

Abstract: Cyclic microindentation experiments were performed using Vickers indenter to investigate whether microindentation induce phase transformations within amorphous silicon layer formed onto the machined surface after single point diamond turning. Although the microindentation induced phase transformation shows direct relationship with crystallographic direction during cyclic microindentation of silicon single crystal, the similar behavior was never probed into machined induced amorphization samples. Phase transformation was probed by micro Raman spectroscopy, which revealed direct evidence not only of recrystallization but also the multiple phase generation. The results indicated that the direction [100] presented as more susceptible to undergo phase transformation and achieve multiple phases with less microindentation cycles than the [110] one. [Copyright &y& Elsevier]