Characterization of crystal structure and precipitation crystallography of a new MgxAl2−xGd phase in an Mg97Al1Gd2 alloy

• Published in: Journal of applied crystallography Vol. 49; no. 4; pp. 1177 - 1181
• Main Authors: Gu, X.-F., Furuhara, T.
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01.08.2016
• Subjects: atomic matching; interfaces; Laves phase; Mg-Al-Gd; orientation relationships
• ISSN: 1600-5767; 1600-5767
• DOI: 10.1107/S1600576716008980

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 MgxAl2−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. The composition, crystal structure and precipitation crystallography of a newfound MgxAl2−xGd precipitate are characterized by Cs‐corrected scanning transmission electron microscopy.