Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7951949 | Journal of Materials Science & Technology | 2018 | 25 Pages |
Abstract
Composition homogenization in solid solution is important for industrial alloys. In the present work, a solute homogenization model is proposed based on the chemical short-range-order tendency in Mg-Gd-based alloys. After a calculation using the cluster-plus-glue-atom model, the stable Mg-Gd structural unit is derived, [Gd-Mg12]Mg6, where one solute Gd is nearest-neighbored with twelve Mg atoms to form the characteristic hcp cluster [Gd-Mg12] and this cluster is matched with six Mg glue atoms. Such a local unit is then mixed with [Mg-Mg12]Mg3, the stable unit for pure Mg. Assuming that the Gd-containing units are arranged in fcc- or bcc-like lattice points and the Mg units in their octahedral interstices, three proportions between the two units are obtained, 1:1, 2:3, and 1:3, which constitute three solute homogenization modes. The prevailing Mg-Gd-based alloys are consequently classified into three groups, respectively exemplified by GW103Â K (Mg-10Gd-3Y-0.4Zr, wt%), GW83Â K (Mg-8Gd-3Y-0.4Zr), and GW63Â K (Mg-6Gd-3Y-0.4Zr). Mg-Gd-Y-Zr alloys were designed following the model (where Y and Zr were also added in substitution for Gd) and prepared by permanent-mould casting. According to their mechanical properties, the 1:3 alloy (Mg-5.9Gd-1.6Y-0.4Zr) shows the best comprehensive properties (ultimate tensile strength 305Â MPa, yield strength 186Â MPa, elongation 9.0%) in solution plus ageing state.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Chemistry
Authors
Shengnan Qian, Chuang Dong, Tianyu Liu, Ying Qin, Qing Wang, Yujuan Wu, Lidong Gu, Jianxin Zou, Xiangwen Heng, Liming Peng, Xiaoqin Zeng,