Crystallographic orientation relationships between the aggregated intermetallic phases in a casting Mg-Ag-Al alloy

Shuhui Lv; Xiaoling Lu; Yanwei Li; Fanzhi Meng; Xiru Hua; Qiang Yang; Xin Qiu; Jian Meng; Qian Duan

Materials & Design (May 2020)

Crystallographic orientation relationships between the aggregated intermetallic phases in a casting Mg-Ag-Al alloy

Shuhui Lv,
Xiaoling Lu,
Yanwei Li,
Fanzhi Meng,
Xiru Hua,
Qiang Yang,
Xin Qiu,
Jian Meng,
Qian Duan

Affiliations

Shuhui Lv: School of Materials Science and Engineering, Changchun University of Science and Technology, 130022, PR China
Xiaoling Lu: School of Materials Science and Engineering, Changchun University of Science and Technology, 130022, PR China
Yanwei Li: School of Materials Science and Engineering, Changchun University of Science and Technology, 130022, PR China
Fanzhi Meng: School of Materials Science and Engineering, Changchun University of Science and Technology, 130022, PR China; Corresponding authors.
Xiru Hua: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China; Key Laboratory of Superlight Materials & Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001, PR China
Qiang Yang: School of Materials Science and Engineering, Changchun University of Science and Technology, 130022, PR China; Key Laboratory of Superlight Materials & Surface Technology, Ministry of Education, Harbin Engineering University, Harbin 150001, PR China; Corresponding authors.
Xin Qiu: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China
Jian Meng: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China
Qian Duan: School of Materials Science and Engineering, Changchun University of Science and Technology, 130022, PR China

Journal volume & issue: Vol. 190

Abstract

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Aggregated eutectic intermetallic phases in a casting Mg-Ag-Al alloy were characterized using transmission electron microscopy. Three kinds of intermetallic phases, namely ε-Mg3Ag (or ε-Mg26−xAg7+x), β′-Mg2(Al,Ag)3, and γ-Mg17Al12, were observed to aggregate together following certain crystallographic orientation relationships (ORs) as: (001)ε//(11¯2)γ and [100]ε//[110]γ (OR1), (001)ε//(110)γ and [001]ε//[110]γ (OR2), (011¯)β′//(1¯10)γ and [100]β′//[110]γ, and (001)β′//(010)ε and [100]β′//[100]ε. TEM observations combined with the corresponding phase diagrams reveal that the ε phase firstly formed during solidification, then the γ phase nucleated on the ε phase, and finally, the β′ phase nucleated on the γ phase. This special intermetallic phase composition which owns numerous fine particles and many semi-coherent interphase boundaries results in high-strength and high-ductility for the casting QA61 alloy. Keywords: Magnesium alloys, Transmission electron microscopy (TEM), Intermetallic phase, Orientation relationship, Formation mechanism

Published in Materials & Design

ISSN: 0264-1275 (Print); 1873-4197 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials
Website: https://www.journals.elsevier.com/materials-and-design

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