(Al, Mg)3La: a new phase in the Mg–Al–La system. Issue 4 (11th July 2018)

• Record Type: Journal Article
• Authors: Wong, Charlotte; Styles, Mark J.; Zhu, Suming; Qiu, Dong; McDonald, Stuart D.; Zhu, Yuman; Gibson, Mark A.; Abbott, Trevor B.; Easton, Mark A.
• Is Part Of: Acta crystallographica. Volume 74:Issue 4(2018:Aug.)
• Page Start: 370
• Page End: 375
• Publication Date: 2018-07-11
• Subjects: (Al, Mg)3La phase -- synchrotron powder diffraction -- Rietveld refinement -- simulated annealing -- high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) imaging
• DOI: 10.1107/S205252061800834X
• Languages: English
• ISSNs: 2052-5206

Abstract

Abstract : A new intermetallic phase has been identified in the Mg–Al–La system with the composition of (Al, Mg)3 La. The crystal structure of this phase [ C 2221, a = 4.3365 (1), b = 18.8674 (4) and c = 4.4242 (1) Å] has been resolved using high‐resolution synchrotron X‐ray powder diffraction and verified by high‐angle annular dark‐field scanning transmission electron microscopy imaging. Abstract : During an investigation of the Mg‐rich end of the Mg–Al–La system, a new ternary phase with the composition of (Al, Mg)3 La was identified. The crystal structure of this phase was determined by conventional X‐ray powder diffraction and transmission electron microscopy analysis and refined using high‐resolution X‐ray powder diffraction. The (Al, Mg)3 La phase is found to have an orthorhombic structure with a space group of C 2221 and lattice parameters of a = 4.3365 (1) Å, b = 18.8674 (4) Å and c = 4.4242 (1) Å, which is distinctly different from the binary Al3 La phase ( P 63 / mmc ). The resolved structure of the (Al, Mg)3 La phase is further verified by high‐angle annular dark‐field scanning transmission electron microscopy.