含Ni夹杂的纳米晶Cu基体力学性能分子动力学模拟

通过拉伸加载的方式研究以Cu为基体、Ni为夹杂的Cu/Ni纳米晶薄膜的力学性能,以及夹杂尺寸、形状对薄膜屈服强度的影响。基于原子嵌入势函数,运用分子动力学方法分析夹杂与位错的相互作用。结果表明:Ni夹杂的引入降低了材料的屈服强度;而在塑性变形阶段依靠界面及Ni原子间较强的相互作用力,夹杂能够阻碍位错的传播,起到强化作用。对于正方形、横置矩形、圆形和竖置矩形的夹杂,当横截面积为6.9nm~2时,薄膜的屈服强度接近;当横截面积为15.7nm~2时,含横置矩形夹杂的薄膜具有最大屈服强度,为7.41MPa;当横截面积为3.1nm~2时,含圆形夹杂的薄膜具有最大屈服强度,为6.93MPa。

Molecular Dynamics Simulations on Mechanical Properties of Substrate Cu with Impurity Ni

The mechanical properties of Cu/Ni film composed of substrate Cu and impurity Ni, and the influence of impurity sizes and shapes on yield strength was studied under tensile loading. Based on the embedded-atom-method potential, molecular dynamics simulations were carried out to analyze the interactions between the impurity and dislocations. The results show that the introduction of impurity Ni decreases the yield strength of the nano-crystalline. However, the impurity hinders the movement of dislocations because of the interface between Cu and Ni, and it strengthens the substrate due to the strong interaction force of Ni in the plastic deformation stage. The films with the shape of square, transverse rectangular, circular and vertical rectangular impurities have similar yield strengths at the cross-sectional size 6. 9nm2; if the cross-sectional size is 15. 7nm2, the film with transverse rectangular impurity has the largest yield strength 7. 41MPa; at the cross-sectional size 3. 1nm2, film with circular impurity has the highest yield strength 6. 93MPa.