Atomically-informed dislocation dynamics model for prediction of void hardening in irradiated tungsten

• Published in: International journal of plasticity 2023-10, Vol.169, p.103727, Article 103727
• Main Authors: Liu, Guisen, Wu, Kaitao, Yu, Ping, Cheng, Xianhao, Shi, Jiaqing, Ye, Changqing, Mao, Yong, Shen, Yao
• Format: Article
• Language: English
• Subjects: Dislocation; Dislocation dynamics; Irradiation hardening; Tungsten; Void
• ISSN: 0749-6419
• DOI: 10.1016/j.ijplas.2023.103727

•A void-dislocation interaction model is developed by integrating their elastic interaction and direct contact interaction.•The parameters of the interaction model are determined by atomistic simulations.•After implementing the interaction model in DD code, hardening effects of voids in irradiated tungsten is comprehensively studied by DD simulation.•An MFKH model is proposed to quantify the hardening of nanometric voids with random spatial distribution based on DD results.•The MFKH model exhibits good predictive ability of void hardening when comparing with experiments. Nanometric voids are one of the fundamental defects generated by neutron irradiation in fusion environment, which impede dislocation motion and cause hardening of plasma facing tungsten. Accurate prediction of voids hardening is crucial for safety evaluation of irradiated tungsten. In this paper, we develop a void-dislocation interaction model within the framework of dislocation dynamics (DD) and implement it in open-source DD software ParaDiS. We use this model to study the hardening effects of randomly-distributed voids with different sizes and number densities. The model for short-range interaction during dislocation-void contact, especially the dislocation movement on void surface, is informed and calibrated by atomistic simulations. Meanwhile, the long-range elastic interaction between dislocation and void is efficiently computed by the approach developed in our recent work (Wu et al., 2022) with Eshelby's equivalent inclusion method. Our DD simulations show that the average resistance by voids with various sizes is proportional to the 2/3 power of total number density. We also find that a modified Friedel-Kroupa-Hirsch (MFKH) model can quantify the hardening effects of nanometric voids, where the hardening coefficient depends on an effective average void diameter that accounts for the size distribution of voids. This MFKH model extends our previous work (Wu et al., 2022) that addresses the hardening of small vacancy clusters where dislocations simply cut through them, which is essentially an elastic perturbation to the dislocation dynamics. The proposed MFKH model can predict both small vacancy clusters and nanometric voids hardening effects with only difference in size dependent hardening coefficient. We further verify the MFKH model by comparing its quick predictions of the hardening effects by randomly-distributed nanometric voids with experiments on twelve neutron-irradiated tung