Structural modification mechanism of Fe-based amorphous alloys by high-energy particle irradiation

Abstract

High-energy particle irradiation-induced crystallization technology presents remarkable potential for precise nanostructure design. However, the fundamental mechanism behind this process remains a long-standing unsolved puzzle. In this paper, we used a high-energy electron beam as the irradiation source and amorphous Fe85B15 alloy as a model system to investigate the behavior of irradiation-induced structural changes. Our experimental results show that the nucleation barrier in irradiation-induced crystallization ranges from 0.5 to 0.8 eV, depending on the temperature, much smaller than that observed in thermal-induced crystallization. Additionally, the nucleation entropy observed is −1.60 × 10−3 eV/K, and the entropic contribution to the nucleation barrier dominates over the enthalpic contribution. This paper provides compelling experimental evidence demonstrating that nucleation in irradiation-induced crystallization is not a thermally activated effect; instead, it is a process in which the amorphous state progresses through a series of intermediate short-range ordering configurations toward a crystalline state with the assistance of irradiation-induced atomic rearrangement.