Crack-healing mechanisms in high-entropy alloys under ion irradiation

High-entropy alloys (HEAs) are potential candidates for advanced nuclear structural materials due to their impressive mechanical properties under extreme conditions. However, micro-cracks, the most common material damage, are introduced upon of the material synthesis and in service. In this work, an atomistic investigation of the crack-healing mechanisms of a FeCoCrNiAl0.5 HEA under ion irradiation is provided by molecular dynamics simulations. Quantitative analysis of the generation and recombination of point defects during the process of overlapping collision cascades is implemented to assess the crack-healing mechanisms in the HEA. The interstitial defects generated in the core of the cascade during the first collision event diffuse to the crack surface, resulting in crack-healing during subsequent recrystallization. In addition, the corresponding vacancies accumulate and forms large-size vacancy clusters that generate stacking faults and complex dislocation networks distributed around the location of the healed crack. With increasing the number of overlapping cascades the defects recombination rate increases and the phase stability is further improved. Crack-healing engineering in HEAs subjected to ion irradiation could pave the way towards designing advanced nuclear materials.