Multiscale modeling of irradiation-induced defect evolution in BCC multi principal element alloys

作者：Xiong, Yaoxu; Zhang, Jun; Ma, Shihua; Huang, Shasha; Xu, Biao; Zhao, Shijun^*

来源：Journal of Alloys and Compounds, 2023, 953: 170084.

DOI：10.1016/j.jallcom.2023.170084

• Multi-principal element alloys
• Radiation damage
• Molecular dynamics
• Displacement energy
• Defect evolution
• Cluster dynamics

Multi-principal element alloys (MPEAs) have garnered significant attention due to their exceptional me-chanical properties and resistance to irradiation. The changes in microstructures under irradiation are in-fluenced by the primary damage state and the diffusion and interaction of defects over a prolonged period, presenting a problem that spans several scales. In this work, we present a multiscale modeling of defect evolution in body-centered cubic (BCC) MPEAs by combining molecular dynamics (MD) and cluster dy-namics (CD) for the first time, which enables us to link the microscopic scale defect process with the experimentally observable defect structures at a mesoscopic scale and to analyze the critical factors af-fecting the irradiation performance of MPEAs. In contrary to previous reports on face-centered cubic (FCC) MPEAs, our MD simulations show that the random arrangement of different elements in MPEAs strongly suppresses intra-cascade cluster formation, even compared with their corresponding averaged alloy models (AAM). We then utilize the primary damage states from MD simulations to feed into a CD model and show that cluster growth in random MPEAs is inhibited during the reaction-diffusion stage due to the slower and three-dimensional defect dynamics compared with their corresponding AAMs. Our results elucidate the unique irradiation resistance mechanism of BCC MPEAs and provide essential guidelines for alloy design with controllable defect dynamics.