Bringa Eduardo M, Caro Alfredo, Wang Yinmin, Victoria Maximo, McNaney James M, Remington Bruce A, Smith Raymond F, Torralva Ben R, Van Swygenhoven Helena
Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
Science. 2005 Sep 16;309(5742):1838-41. doi: 10.1126/science.1116723.
Molecular dynamics simulations of nanocrystalline copper under shock loading show an unexpected ultrahigh strength behind the shock front, with values up to twice those at low pressure. Partial and perfect dislocations, twinning, and debris from dislocation interactions are found behind the shock front. Results are interpreted in terms of the pressure dependence of both deformation mechanisms active at these grain sizes, namely dislocation-based plasticity and grain boundary sliding. These simulations, together with new shock experiments on nanocrystalline nickel, raise the possibility of achieving ultrahard materials during and after shock loading.
对冲击载荷下纳米晶铜的分子动力学模拟显示，在冲击波阵面之后存在意想不到的超高强度，其值高达低压下的两倍。在冲击波阵面之后发现了部分位错和全位错、孪晶以及位错相互作用产生的碎片。根据在这些晶粒尺寸下起作用的两种变形机制（即位错基塑性和晶界滑动）的压力依赖性对结果进行了解释。这些模拟以及对纳米晶镍进行的新的冲击实验，增加了在冲击加载期间及之后获得超硬材料的可能性。
