The structure of a long-period stacking phase in an Mg-Al-Y alloy studied by electron microscopy

• Published in: Philosophical magazine (Abingdon, England) Vol. 98; no. 24; pp. 2247 - 2256
• Main Authors: Takeda, Mitsuhiro, Konno, Kazuya, Yasuhara, Akira, Hiraga, Kenji
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 23-08-2018
• Subjects: electron microscopy; long-period stacking structure; Magnesium alloy; magnesium-aluminum-yttrium; ordered structure; STEM
• ISSN: 1478-6435; 1478-6443
• DOI: 10.1080/14786435.2018.1480837

A new phase with a 10H-type long-period stacking (LPS) structure was found in an Mg
75
Al
10
Y
15
alloy annealed at 823 K. The LPS structure in the Mg
75
Al
10
Y
15
alloy annealed at 823 K for 2 h has an ordered arrangement of L1
2
-type structural Al
6
Y
8
clusters on the two-dimensional plane parallel to the c-plane of hexagonal Mg lattice and a disordered arrangement along the c-axis, whereas a perfectly ordered structure along the c-axis, which has a period with two times of that of the 10H-type LPS structure, was established by annealing at 823 K for 24 h. The structural model of the ordered LPS phase is proposed by high-resolution images taken with a Cs-corrected scanning transmission electron microscope and also electron diffraction patterns.