Liu Cuixia, Yang Yuchia, Xia Zhenhai
School of Materials Science and Chemical Engineering, Xi'an Technological University Xi'an Shaanxi 710021 China
Department of Materials Science and Engineering, Department of Chemistry, University of North Texas Denton TX 76203 USA.
RSC Adv. 2020 Jul 24;10(46):27688-27696. doi: 10.1039/d0ra01885f. eCollection 2020 Jul 21.
High entropy alloys (HEAs), composed of multiple components with equal or near atomic proportions, have extraordinary mechanical properties and are expected to bear the impact of high-speed forces in armor protection structure materials. In order to understand the deformation behaviour of HEAs under tensile and compressive loading, molecular dynamics simulations were performed to reveal the deformation mechanism and mechanical properties of three crystal structures: AlCoCrFeNi HEAs without grain boundaries (perfect HEAs), AlCoCrFeNi HEAs with grain boundaries of Σ3(111)[11̄0] (GBs HEAs) and grain boundaries of Σ3(111)[11̄0] with chemical cluster HEAs (cluster-GBs HEAs). The mechanical properties of the three models at the same strain rate were discussed. Then, the mechanical properties at different strain rates were analyzed. The movement and direction of internal dislocations during the deformation process were investigated. The simulation results show that the GBs HEAs and the cluster-GBs both play an important role in the deformation and failure of the HEAs. Under tensile loading, three behaviour stages of deformation were observed. Cluster-GBs HEAs have a larger yield strength and Young's modulus than that of GBs and perfect HEAs. The higher the strain rate is, the greater the stress reduction rate. Under compressive loading, there are only two behaviour stages of deformation. Cluster-GBs HEAs also have the largest yield strength. Under tensile and compressive deformation, Shockley partial dislocations of 1/6 <112> are dominant and their moving direction and effect on mechanical properties are discussed.
高熵合金（HEAs）由多种原子比例相等或相近的成分组成，具有非凡的力学性能，有望承受装甲防护结构材料中高速力的冲击。为了了解高熵合金在拉伸和压缩载荷下的变形行为，进行了分子动力学模拟，以揭示三种晶体结构的变形机制和力学性能：无晶界的AlCoCrFeNi高熵合金（完美高熵合金）、具有Σ3(111)[11̄0]晶界的AlCoCrFeNi高熵合金（晶界高熵合金）以及具有化学团簇的Σ3(111)[11̄0]晶界的高熵合金（团簇-晶界高熵合金）。讨论了三种模型在相同应变率下的力学性能。然后，分析了不同应变率下的力学性能。研究了变形过程中内部位错的运动和方向。模拟结果表明，晶界高熵合金和团簇-晶界高熵合金在高熵合金的变形和失效中都起着重要作用。在拉伸载荷下，观察到三个变形行为阶段。团簇-晶界高熵合金比晶界高熵合金和完美高熵合金具有更大的屈服强度和杨氏模量。应变率越高，应力降低率越大。在压缩载荷下，只有两个变形行为阶段。团簇-晶界高熵合金也具有最大的屈服强度。在拉伸和压缩变形下，1/6 <112>的肖克利不全位错占主导地位，并讨论了它们的运动方向及其对力学性能的影响。
