辐照条件下空洞超点阵形成过程的相场模拟

钨（W）具有高熔点、高热导率和优异的抗辐照能力等优点，是未来聚变堆面向等离子体部件的重要候选材料。然而中子辐照后的纯W中会产生空洞超点阵，严重影响其服役性能。本文改进了辐照条件下纯W中空洞超点阵形成过程的相场模型，采用更合理的体系总自由能函数表达形式，且考虑了空间与时间上随机分布的辐照点缺陷的产生。模拟结果表明：辐照过程中，间隙原子的定向扩散及其与空位的相互作用是空洞超点阵形成的主要原因；间隙原子沿不同方向的定向扩散形成了不同类型的空洞点阵；点阵中空洞的排列会随模拟时间的延长变得有序，空洞尺寸也会变得基本一致，而空洞形状并非标准的圆形，模拟结果与实验结果基本一致。

Phase-field Simulation of Void Superlattice Formation during Irradiation

Due to its high melting point, high thermal conductivity and strong irradiation resistance, tungsten (W) has been regarded as an important candidate material for plasma facing components of future fusion reactor. However, the void superlattice produced in pure W during irradiation seriously affects its properties. In this paper, the phase-field model of void superlattice formation in pure W during irradiation was improved, and the generation of irradiation point defect with random distribution in space and time was used. The simulation results show that the directional diffusion of interstitial atom and its interaction with vacancy lead to the formation of void superlattice during irradiation. The directional diffusion of interstitial atom along different directions leads to the different types of void lattice. The arrangement of voids in the lattice becomes orderly with the extension of simulation time, and the size of hole becomes basically the same. However, the shape of void is not a standard circle, which is consistent with the experimental results.