First-Principles Investigation of the Early-Stage Precipitations in Mg-Sn and Mg-Zn Alloys
First-Principles Investigation of the Early-Stage Precipitations in Mg-Sn and Mg-Zn Alloys
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DOI：
10.1007/978-3-030-92533-8_47
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
D. Cheng;K. Wang;B. Zhou
中科院分区：
文献类型：
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作者：
D. Cheng;K. Wang;B. Zhou
Mg-Sn和Mg-Zn合金具有较强的时效硬化效应，是制备高强度、低成本镁合金的理想基体。然而，这些系统中热处理过程中各种沉淀物和金属间化合物的原子结构和相稳定性仍不清楚。在这里，我们使用第一性原理计算和集团展开（CE）相结合的方法来调查的原子结构和热力学稳定性的实验报告的沉淀物，以及在FCC和HCP晶格上的Mg-Sn和Mg-Zn合金的排序。从低能量结构搜索CE，潜在的Guinier-Preston（GP）区确定从首选HCP排序。与Mg-Sn体系相比，HCP Mg-Zn体系的CE收敛较慢，这是由于较大的晶格失配导致的长程相互作用。该研究有助于设计更好的时效硬化镁合金。
Mg-Sn and Mg-Zn alloys exhibit a strong age-hardening effect and have become promising bases for high-strength and low-cost Mg alloys. However, the atomic structures and phase stabilities of various precipitates and intermetallic compounds during the heat treatment in these systems remain unclear. Here we use a combined approach of first-principles calculations and cluster expansion (CE) to investigate the atomic structures and thermodynamic stabilities of the experimentally reported precipitates as well as orderings on the FCC and HCP lattices in Mg-Sn and Mg-Zn alloys. From the low energy structures searched by CE, potential Guinier–Preston (GP) zones are identified from preferred HCP orderings. The slow convergence for CE of HCP Mg-Zn, compared with that of Mg-Sn system, is attributed to the long-ranged interactions resulting from the larger lattice mismatch. This study could help design better age-hardened Mg alloys.