Collision cascades near a 1/2⟨111⟩{110} edge dipole in alpha-iron have been studied using molecular dynamics simulations for a recoil energy of 20 keV and two temperatures, 20 K and 300 K. These simulations show that the collision cascade induces the migration of the dislocations through glide along its slip plane. The motion of the dislocations starts at the peak of the collision cascade and expands a time scale much longer than the cascade duration, until restoring the equilibrium distance of the dipole, regardless of the damage produced by the cascade. At the initial stages, kinks are formed at the dislocation that enhance glide. When defects reach the dislocations, jogs are produced. We show that the initial dislocation motion is triggered by the shock wave of the collision cascade. The cascade morphology is also strongly influenced by the presence of the dislocations, having an elongated form at the peak of the displacement, which demonstrates the strong interaction of the dislocations with the cascade even at the early stages. Finally, we show that larger vacancy clusters are formed in the presence of dislocations compared to isolated cascades and that these clusters are larger for 300 K compared to 20 K.

使用分子动力学模拟研究了20 keV的反冲能量和20 K和300 K的两个温度下，α-铁中1 /2⟨111⟩{110}边缘偶极子附近的碰撞级联。这些模拟表明，碰撞级联通过滑移沿其滑动面引起位错迁移。位错的运动始于碰撞级联的峰值，并且扩展了比级联持续时间长得多的时间标度，直到恢复偶极子的平衡距离为止，而不管级联所产生的损害如何。在初始阶段，在位错处会形成扭结，从而增加滑行。当缺陷到达位错时，就会产生点动。我们表明，初始位错运动是由碰撞级联的冲击波触发的。级联形态也受到位错的存在的强烈影响，位错在位移的峰值处呈拉长的形式，这表明位错与级联的强烈相互作用甚至在早期也是如此。最后，我们显示，与分离的级联反应相比，在位错存在下会形成较大的空位簇，并且与20 K相比，这些簇在300 K时更大。