论文标题
锆中位错环特性的原子建模研究
An Atomistic Modelling Study of the Properties of Dislocation Loops in Zirconium
论文作者
论文摘要
中子辐照逐渐改变了锆合金的特性：它们硬化，平均C/A晶格参数比随着通量而降低。中子的轰击会产生点缺陷，后者演变为脱位环，导致一种称为辐射诱导的生长（IIG）的不均匀生长现象。为了了解ZR中这些错位回路的见解，我们使用原子模拟对它们进行了研究。我们构建了各种类型的放松位错环。我们发现，不同习惯平面上的<a>环的能量是相似的，但是我们的结果表明，它们最有可能在第一个棱镜平面上形成，然后通过旋转到第二个棱镜平面来减少其能量。通过模拟不同纵横比的循环，我们发现，仅基于能量学，<a> - 环的形状不取决于特征，并且随着大小的增加，这些环变得越来越椭圆形。此外，我们发现间质<c/2+p> - 环和空位<c> - 环在能量上都是可行的，因此应在将来的工作中考虑这些可能性。我们的发现提供了有关循环形成和进化的重要见解，这些见解很难通过实验进行探测。
Neutron irradiation progressively changes the properties of zirconium alloys: they harden and their average c/a lattice parameter ratio decreases with fluence. The bombardment by neutrons produces point defects, which evolve into dislocation loops that contribute to a non-uniform growth phenomenon called irradiation-induced growth (IIG). To gain insights into these dislocation loops in Zr we studied them using atomistic simulation. We constructed and relaxed dislocation loops of various types. We find that the energies of <a>-loops on different habit planes are similar, but our results indicate that they are most likely to form on the 1st prismatic plane and then reduce their energy by rotating onto the 2nd prismatic plane. By simulating loops of different aspect ratios, we find that, based on energetics alone, the shape of <a>-loops does not depend on character, and that these loops become increasingly elliptical as their size increases. Additionally, we find that interstitial <c/2+p>-loops and vacancy <c>-loops are both energetically feasible and so the possibility of these should be considered in future work. Our findings offer important insights into loop formation and evolution, which are difficult to probe experimentally.
