A review of radiation effects and tribological behavior in multi-principal element alloys: towards extreme environment applications

Structural materials for next-generation nuclear and aerospace systems must endure the simultaneous rigors of intensive irradiation and mechanical wear, where conventional alloys succumb to catastrophic swelling and accelerated degradation. Multi-principal element alloys (MPEAs) have emerged as promising candidates, leveraging core effects such as severe lattice distortion and sluggish diffusion to enhance point-defect recombination and structural stability. Concurrently, MPEAs exhibit exceptional tribological resilience across wide temperature ranges, facilitated by deformation-induced phase transformations at low temperatures and the formation of protective self-lubricating glaze layers at elevated temperatures. Despite these advances, a critical knowledge gap persists regarding the synergistic coupling between irradiation damage and tribological performance. This review synthesizes current progress in irradiation and wear studies, highlighting the potential for MPEAs to mitigate radiation-induced embrittlement and leverage friction-induced structural refinement to enhance radiation tolerance. We emphasize the transformative role of multi-scale computation, bridging ab initio methods with machine-learning-assisted molecular dynamics, in deciphering these coupled phenomena. Finally, we identify key research challenges, such as the lack of in situ coupled studies, and outline future directions involving integrated experiments, machine-learning-accelerated design, and the development of adaptive MPEA-based coatings for extreme environments.