First-principles study of coherent interfaces of Laves-phase MgZn2 and stability of thin MgZn2 layers in Mg-Zn alloys

JOURNAL OF ALLOYS AND COMPOUNDS

卷:696

Article

Xie, Yao-Ping¹ 

[1] Shanghai Univ, Sch Mat Sci & Engn, Key Lab Microstruct, Shanghai 200072, Peoples R China

关键词: Mg alloys;    Precipitates;    Laves-phase MgZn2;    Orientation relationships;    First-principles calculations;   

DOI  :  10.1016/j.jallcom.2016.11.217

来源: Elsevier

【 摘 要 】

The beta(1)' and beta(2)' are important precipitates in Mg-Zn alloys. Two types of precipitates both are composed of MgZn2, but the orientation relationships of MgZn2 with the alpha-Mg matrix in two precipitates are different. To understand the properties of beta(1)' and beta(2)', we use the first-principles method to perform a systematical investigation of coherent interfaces of beta(1)'/alpha-Mg and beta(2)'/alpha-Mg. Here, we present exhaustive analysis of the structure and stability for these interfaces, and find that the interfacial energy is highly dependent on the average coordination of interfacial structures. Furthermore, we find that the MgZn2 slab in matrix with [11 (2) over bar0](MgZn2)//[0001](alpha), (0001)(MgZn2)//(11 (2) over bar0)(alpha) orientation relationship (OR1) is less stable than that with [11 (2) over bar0](MgZn2)//[10 (1) over bar0](alpha), (0001)(MgZn2)//(0001)(alpha) orientation relationship (OR2), which can explain that the beta(2)' plate shape precipitates that are frequently observed in Mg-Zn alloys comply with OR2 instead of OR1. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

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