图 1  $\left\langle 100 \right\rangle $间隙型位错环与表面相互作用计算模型示意图　(a)和(b)单个位错环与表面的相互作用模型, 其中位错环伯格斯矢量分别平行(a)和垂直(b)于表面法线方向; (c)两个不同的具有相互作用的伯格斯矢量的$\left\langle 100 \right\rangle $位错环与表面相互作用的微观模型; 图中位错环和表面原子的颜色根据其势能E_pot大小确定, 如图中的能量颜色棒表示, 在表面之外为真空层, 以模拟表面与位错环的相互作用过程

Fig. 1.  Schematic of interaction between $\left\langle 100 \right\rangle $ loop(s) with {100} surface: (a) and (b) Interaction between a single $\left\langle 100 \right\rangle $ loop with surface with Burgers vector parallel (a) or perpendicular (b) to the normal line of surface; (c) interaction between two interacting $\left\langle 100 \right\rangle $ loops and {100} surface. The atoms in loops and surface are colored by their potential energies E_pot as marked by the color bar in the Fig. 1.

图 2  $\left\langle 100 \right\rangle $位错环伯格斯矢量平行于表面法线方向, 300 K时位错环的演化过程　(a)−(c)位错环向表面运动过程示意图; (d)−(g)位错环与表面发生反应过程; (h)位错环最终被表面吸收后的状态

Fig. 2.  Evolution of a $\left\langle 100 \right\rangle $ dislocation loop at 300 K with its Burgers vector along the normal direction of surface of {100}. The motion processes of loop are shown in panel (a) to (c) before its interaction with surface, which are shown in panel (d) to (g). Panel (h) is the final state after the absorption of loop by surface.

图 3  $\left\langle 100 \right\rangle $位错环伯格斯矢量垂直于表面法线方向时不同温度下位错环的演化过程　(a)温度为300 K, 模拟时间为224 ps; (b)温度为300 K、模拟时间653.6 ps; (c)温度为585 K, 模拟时间为1731.4 ps; (d)温度为740 K, 模拟时间为523.9 ps; (e)温度为970 K, 模拟时间为822.5 ps; (f)温度为1220 K, 模拟时间为129.9 ps; (g)温度为1220 K, 模拟时间为139.9 ps; (h)温度为1220 K, 模拟时间为149.9 ps

Fig. 3.  Evolution of a $\left\langle 100 \right\rangle $ dislocation loop at different temperatures with its Burgers vector perpendicular to the normal direction of {100} surface. The results simulated at 300 K are shown in (a) and (b) with simulation time up to 224 ps and 653.6 ps, respectively. The results simulated at 585 K, 740 K and 970 K are shown in (c) to (e) with simulation time up to 1731.4 ps, 523.9 ps, 822.5 ps, respectively. The results at 1220 K with simulation time up to 129.9 ps, 139.9 ps, 149.9 ps are shown in (f) to (h), respectively.

图 4  $\left\langle 100 \right\rangle $位错环伯格斯矢量平行于表面法线方向时, 不同温度下位错环的位置演化

Fig. 4.  Position of a $\left\langle 100 \right\rangle $ dislocation loop with increasing the simulation time. The Burgers vector of loop is parallel to the normal direction of {100} surface.

图 5  伯格斯矢量相互垂直的双位错环的演化过程　(a)−(c)模拟温度为300 K, 模拟时间分别为10 ps, 20 ps, 30 ps; (d)−(h)模拟温度为900 K, 模拟时间分别为98.5 ps, 108.4 ps, 118.3 ps, 128.1 ps, 138 ps

Fig. 5.  Evolution of two $ \left\langle 100 \right\rangle $ dislocation loops at 300 K and 900 K with Burgers vector perpendicular to each other The results obtained at 300 K are shown (a) to (c) with simulation time up to 10 ps, 20 ps, 30 ps, respectively. The results obtained at 900 K are shown (d) to (h) with simulation time up to 98.5 ps, 108.4 ps, 118.3 ps, 128.1 ps, 138 ps, respectively.

图 6  伯格斯矢量平行于表面法线方向的$ \left\langle 100 \right\rangle $位错环与表面相互作用后的表面形貌

Fig. 6.  Surface morphology of {100} plane after its absorption of a $ \left\langle 100 \right\rangle $ dislocation loop with its Burgers vector along the normal direction of {100} surface.