Jiang Dong-Dong, Chen Peng-Yu, Wang Pei, He An-Min
Institute of Applied Physics and Computational Mathematics, Beijing 100094, China.
Graduate School of China Academy of Engineering Physics, Beijing 100088, China.
Nanomaterials (Basel). 2021 Oct 3;11(10):2603. doi: 10.3390/nano11102603.
In this study, the effects of Cu nanoparticle inclusion on the dynamic responses of single crystal Al during shockwave loading and subsequent spallation processes have been explored by molecular dynamics simulations. At specific impact velocities, the ideal single crystal Al will not produce dislocation and stacking fault structure during shock compression, while Cu inclusion in an Al-Cu nanocomposite will lead to the formation of a regular stacking fault structure. The significant difference of a shock-induced microstructure makes the spall strength of the Al-Cu nanocomposite lower than that of ideal single crystal Al at these specific impact velocities. The analysis of the damage evolution process shows that when piston velocity ≤ 2.0 km/s, due to the dense defects and high potential energy at the interface between inclusions and matrix, voids will nucleate preferentially at the inclusion interface, and then grow along the interface at a rate of five times faster than other voids in the Al matrix. When ≥ 2.5 km/s, the Al matrix will shock melt or unloading melt, and micro-spallation occurs; Cu inclusions have no effect on spallation strength, but when Cu inclusions and the Al matrix are not fully diffused, the voids tend to grow and coalescence along the inclusion interface to form a large void.
在本研究中，通过分子动力学模拟探究了铜纳米颗粒夹杂对单晶铝在冲击波加载及随后的层裂过程中动态响应的影响。在特定冲击速度下，理想单晶铝在冲击压缩过程中不会产生位错和堆垛层错结构，而铝铜纳米复合材料中的铜夹杂会导致形成规则的堆垛层错结构。冲击诱导微观结构的显著差异使得在这些特定冲击速度下，铝铜纳米复合材料的层裂强度低于理想单晶铝。对损伤演化过程的分析表明，当活塞速度≤2.0 km/s时，由于夹杂与基体界面处缺陷密集且势能较高，孔洞将优先在夹杂界面形核，然后以比铝基体中其他孔洞快五倍的速率沿界面生长。当≥2.5 km/s时，铝基体将发生冲击熔化或卸载熔化，并出现微层裂；铜夹杂对层裂强度没有影响，但当铜夹杂与铝基体未充分扩散时，孔洞倾向于沿夹杂界面生长并合并形成大孔洞。
