Zhu Xunming, Liu Dan, Wang Jian, Chen Candong, Li Xinxin, Wang Li, Wang Mingxu
School of Mechanical, Electrical & Information Engineering, Shandong University, Weihai 264200, China.
Weihai Wanfeng Magnesium Industry Science and Technology Development Co., Ltd., Weihai 264200, China.
Materials (Basel). 2023 Oct 19;16(20):6768. doi: 10.3390/ma16206768.
To investigate the influence of alloying elements (Zn, Mg, and Cu) on the structural and dynamical properties of liquid Al-9Si alloy, we conducted ab initio molecular dynamics (AIMD) simulations. Our results indicate that the structure of Al-Si-M ternary alloys is determined with a combination of atomic radii and mixing enthalpy, while the dynamic properties are primarily influenced by electronic structure of the alloying elements. Specifically, the addition of Cu promotes the formation of Al-Cu short-range order (SRO), while Zn has a higher propensity for Zn-Zn SRO. The Al-Cu SRO in liquid alloy may serve as the precursor for the AlCu reinforcing phase in Al-Si-Cu alloys. Upon the addition of Mg, a greater number of relatively stable perfect and distorted icosahedral structures, as well as hcp and bcc ordered structures with lower energies, are observed. Additionally, the presence of Mg leads to a reduction in the atomic diffusion rates of Al and Si, while Cu and Zn exhibit complex diffusion behavior influenced by the presence of Si atoms.
为了研究合金元素（锌、镁和铜）对液态Al-9Si合金结构和动力学性质的影响，我们进行了从头算分子动力学（AIMD）模拟。我们的结果表明，Al-Si-M三元合金的结构由原子半径和混合焓共同决定，而动力学性质主要受合金元素电子结构的影响。具体而言，铜的添加促进了Al-Cu短程有序（SRO）的形成，而锌更倾向于形成Zn-Zn SRO。液态合金中的Al-Cu SRO可能是Al-Si-Cu合金中AlCu强化相的前驱体。添加镁后，观察到大量相对稳定的完美和扭曲二十面体结构，以及能量较低的hcp和bcc有序结构。此外，镁的存在导致Al和Si的原子扩散速率降低，而铜和锌表现出受Si原子存在影响的复杂扩散行为。
