Bui Thi-Xuyen, Lu Yu-Sheng, Tsai Sheng-Hsiang, Fang Te-Hua
Department of Mechanical Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, 807, Taiwan.
University of Technology and Education - The University of Danang, Danang, Vietnam.
J Mol Model. 2025 Jan 30;31(2):71. doi: 10.1007/s00894-025-06292-0.
To address the severe fuel crisis and environmental pollution, the use of lightweight metal materials, such as AZ alloy, represents an optimal solution. This study investigates the mechanical behavior and deformation mechanism of AZ alloys under uniaxial compressive using molecular dynamics (MD) simulations. The influence of various compositions, grain sizes (GSs), and temperatures on the compressive stress, the ultimate compressive strength (UCS), compressive yield stress (CYS), Young's modulus (E), shear strain, phase transformation, dislocation distribution, and total deformation length is thoroughly examined. The results show that although AZ91 has the highest Al content, it exhibits the lowest UCS, CYS, and fraction atoms with shear strain larger than 0.2 (FSS0.2) compared to AZ31 and AZ61. At the same time, the total dislocation length of AZ31 is the largest. The effect of GS and temperature on the mechanical response and deformation mechanism of AZ31 alloy indicates that a GS of 7.6 nm is the critical value to determine the mechanical properties and deformation intensity of AZ31 alloy. Moreover, the E, UCS, and CYS values decrease gradually as temperature increases. The compressive stress, E, UCS, CYS, and FSS0.2 of single crystalline AZ31 are higher than those of polycrystalline AZ31 with all GSs. The MD simulation results show that the sample experiences the formation of stacking faults at both single crystalline and polycrystalline AZ31 while forming the shear band at the single crystalline, leading to strong oscillations in compressive stress. In contrast, polycrystalline AZ31, across all GSs, exhibits high shear strain zones, causing oscillations in compressive stress.
The ATOMSK program is used to create the polycrystalline AZ structures. The MD method is employed to investigate the influence of various compositions, GSs, and temperatures on the mechanical properties and deformation mechanism of AZ alloys. All the simulations are performed by LAMMPS software. The visualization tool (OVITO) is used to inspect, analyze, and illustrate the simulation results. The EAM potential is applied to the interactions between Al-Zn, Al-Mg, and Zn-Mg.
为应对严重的燃料危机和环境污染，使用轻质金属材料（如AZ合金）是一种最佳解决方案。本研究采用分子动力学（MD）模拟研究了AZ合金在单轴压缩下的力学行为和变形机制。全面考察了各种成分、晶粒尺寸（GSs）和温度对压缩应力、极限抗压强度（UCS）、抗压屈服应力（CYS）、杨氏模量（E）、剪切应变、相变、位错分布和总变形长度的影响。结果表明，尽管AZ91的Al含量最高，但与AZ31和AZ61相比，其UCS、CYS以及剪切应变大于0.2的原子分数（FSS0.2）最低。同时，AZ31的总位错长度最大。GS和温度对AZ31合金力学响应和变形机制的影响表明，7.6 nm的GS是决定AZ31合金力学性能和变形强度的临界值。此外，随着温度升高，E、UCS和CYS值逐渐降低。所有GSs的单晶AZ31的压缩应力、E、UCS、CYS和FSS0.2均高于多晶AZ31。MD模拟结果表明，样品在单晶和多晶AZ31中均会形成堆垛层错，而在单晶中形成剪切带时会导致压缩应力强烈振荡。相比之下，所有GSs的多晶AZ31均表现出高剪切应变区，导致压缩应力振荡。
使用ATOMSK程序创建多晶AZ结构。采用MD方法研究各种成分、GSs和温度对AZ合金力学性能和变形机制的影响。所有模拟均由LAMMPS软件执行。使用可视化工具（OVITO）检查、分析和说明模拟结果。EAM势用于Al-Zn、Al-Mg和Zn-Mg之间的相互作用。
