Characterization of crystal structure and precipitation crystallography of a new Mg_xAl_2−xGd phase in an Mg₉₇Al₁Gd₂ alloy

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• 作者：X.-F. Gu and T. Furuhara
• 关键词：Mg&ndash ; Al&ndash ; Gd ; Laves phase ; orientation relationships ; interfaces ; atomic matching
• 刊名：Journal of Applied Crystallography
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：49
• 期：4
• 页码：1177-1181
• 全文大小：1099K
• ISSN：1600-5767

文摘

The composition, crystal structure and precipitation crystallography of a newly found precipitate are characterized by Cs-corrected scanning transmission electron microscopy. The composition of the plate-like precipitate could be expressed as Mg_xAl_2−xGd (x = 0.38), and its crystal structure is the same as the face-centered cubic type Laves phases Mg₂Gd and Al₂Gd, with a lattice parameter of 7.92 Å (space group No. 227, ). The orientation relationship between the matrix and precipitate is found to be (0001)_m//(111)_p and [100]_m//[10]_p, and the habit plane is parallel to the (0001)_m//(111)_p plane. In addition, this preferred crystallography of phase transformation is well explained on the basis of the atomic matching at the interface.