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第一性原理研究应力对 6005A 铝合金电子结构和 弹性性质的影响
First-principles Study on the Effect of Stress on the Mechanical and Electronic Structure of 6005A Aluminum Alloy
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- DOI:
- 作者:
- 范乐天
FAN Letian
- 作者单位:
- 中车唐山机车车辆有限公司产品研发中心，河北 唐山 063000
Product R & D Center of CRRC Tangshan Locomotive & Rolling Stock Co., Ltd., Tangshan 063000, China
- 关键词:
- 6005A 铝合金；析出相；第一性原理；力学性能；电子结构；应力
6005A aluminum alloy; precipitated phase; first principles; mechanical properties; electronic structures; stress
- 摘要:
- 6005A 铝合金中的纳米析出相可以有效提高合金的力学性能。 然而，纳米级的尺寸和取向变化极大地阻碍了对析出相之间的潜在关系和晶体结构的理解。因此，本文用第一性原理计算研究了 6005A 铝合金中 Mg 5 Si 6 、 Mg 9 Si 5 和Mg 2 Si 3 种析出相在有无应力条件下的结构稳定性、力学性质和电子结构。 无应力条件下的计算结果与以前的实验和理论结果符合得较好。结果表明，压缩应力不仅会增加 3 种析出相的韧性，还会降低 Mg 2 Si 的带隙。 此外，应力条件下会普遍提高析出相的生成焓和内聚能，从而降低其稳定性，促使亚稳态析出相向稳态析出相转变。 这些发现将有助于进一步理解 6005A 铝合金析出相的结构行为和力学性能，对改善 6005A 铝合金性能具有理论指导意义。
Nanoprecipitates in 6005A aluminum alloy can effectively improve the mechanical properties of the alloy. However, the size and orientation changes at the nanoscale have greatly hindered the understanding of the potential relationships between precipitates and the crystal structure. The structural stability, mechanical properties and electronic structures of Mg 5 Si 6 , Mg 9 Si 5 and Mg 2 Si precipitates in 6005A aluminum alloy with or without stress were studied by first-principles calculations. The calculated results are in good agreement with the previous experimental and theoretical results. The compressive stress can increase the toughness of the three precipitated phases and decrease the band gap of Mg 2 Si. Under stress conditions, the formation enthalpy and cohesive energy of the precipitated phase are generally increased to reduce its stability and promote the transition from a metastable to steady precipitated phase. These findings will help to further understand the structural behavior and mechanical properties of the precipitated phase of 6005A aluminum alloy and have theoretical guiding significance for improving the properties of 6005A aluminum alloy.