Origin of exceptional structural stability in refractory amorphous high-entropy alloys under ion irradiation

Refractory amorphous high-entropy alloys (RAHEAs) are promising candidates for advanced nuclear coating materials due to their superior structural stability and ion irradiation tolerance. However, the atomic-level irradiation damage mechanisms remain poorly understood. In this work, molecular dynamics (MD) simulations are performed to systematically investigate the ion irradiation responses of Ti(Zr)HfNbTa metallic glasses (MGs) at varying primary knock-on atom (PKA) energies and temperatures. Our results show that the collision cascading behaviors in RAHEAs differs significantly from that in crystalline and conventional metallic glass counterparts. Due to atomic sluggish long-range diffusion and reduced dynamic heterogeneities, RAHEAs exhibit suppressed yet spatially uniform atomic dynamics. This leads to slower PKA energy dissipation and a longer trajectory of displacement cascades, with a smaller cascade-affected zone and more rapid structural recovery rate. These features contribute to high global microstructural stability and low ion irradiation damage. As a result, RAHEAs exhibit less degradation in mechanical performance under ion irradiation. This study provides new insights into the ion irradiation resistance mechanisms of RAHEAs, offering guidance for the development of novel radiation-resistant materials.