Electron irradiation-induced nanocrystallization of amorphous Fe85B15 alloy: Evidence for athermal nature

Nanocrystallization of amorphous alloys induced by electronic energy deposition has been frequently reported in recent years. In this paper, the crystallization of amorphous Fe85B15 alloy was performed by electron irradiation with 2 MeV electrons up to a flux of 4.0 × 1024 m−2 s−1. It was found that at 298 K, nanocrystalline Fe–B intermetallic phases formed prior to α-Fe phase, while at 463 K, only the α-Fe phase was observed. This phenomenon cannot be interpreted in terms of the electron-beam heating, but may be attributed to the irradiation-induced increases in the short-range order and atomic diffusivity. Theoretical analysis also showed that the maximum-temperature rise driven by beam heating is much lower than that required for thermal crystallization. Our work offers strong evidence that the irradiation-induced crystallization in amorphous alloys is not a thermal activation process.