Abstract Micro residual stress induced by vacancy defects in aluminum crystals was studied by molecular dynamics. The effects of different sizes of vacancy defects on the initial configuration (stable configuration after energy minimization) are analyzed, which are reflected by the changes of atomic potential energy, atomic displacement and atomic stress. The influence of annealing on the lattice structure of atoms near the vacancy defects and the evolution of the defects in the annealing process are also analyzed. After annealing, the vacancies are filled and the atomic lattice structures near the vacancy also change, adding a HCP lattice structure. The atomic distributions are more uniform and more regular. When the voids are small, the atomic stress decreases obviously after annealing. However, when the voids are large, the atomic stress increases after annealing. The influence range of vacancy defects on the micro residual stress is a spherical space with the center of the void as the center of the sphere, and the radius of the sphere is linear relationship with the radius of the voids. When the void radius is small, the annealing heat treatment method can effectively eliminate or reduce the micro residual stress. When the void radius exceeds threshold value, the micro residual stress increases after annealing. A single annealing heat treatment method cannot effectively eliminate the residual stress, which may need to be combined with other methods to eliminate or reduce the residual stress.

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退火对铝晶体空位缺陷引起的微残余应力影响的分子动力学模拟

摘要 利用分子动力学研究了铝晶体空位缺陷引起的微观残余应力。分析了不同大小的空位缺陷对初始构型（能量最小化后的稳定构型）的影响，这些影响体现在原子势能、原子位移和原子应力的变化上。还分析了退火对空位缺陷附近原子晶格结构的影响以及退火过程中缺陷的演变。退火后，空位被填充，空位附近的原子晶格结构也发生变化，增加了HCP晶格结构。原子分布更均匀，更规则。当空隙较小时，退火后原子应力明显降低。但是，当空隙很大时，退火后原子应力增加。空位缺陷对微观残余应力的影响范围是一个以空洞中心为球心的球面空间，球面半径与空洞半径呈线性关系。当空隙半径较小时，退火热处理方法可有效消除或降低微残余应力。当空隙半径超过阈值时，退火后微观残余应力增加。单一的退火热处理方法不能有效消除残余应力，可能需要结合其他方法来消除或降低残余应力。球体的半径与空隙的半径成线性关系。当空隙半径较小时，退火热处理方法可有效消除或降低微残余应力。当空隙半径超过阈值时，退火后微观残余应力增加。单一的退火热处理方法不能有效消除残余应力，可能需要结合其他方法来消除或降低残余应力。球体的半径与空隙的半径成线性关系。当空隙半径较小时，退火热处理方法可有效消除或降低微残余应力。当空隙半径超过阈值时，退火后微观残余应力增加。单一的退火热处理方法不能有效消除残余应力，可能需要结合其他方法来消除或降低残余应力。