Dynamic observation of FeSiBPCu alloys for crystallization via MeV electron irradiation

Abstract

The nanocrystallization of three kinds of nanocrystalline, soft magnetic FeSiBPCu alloys as well as Fe76Si9B10P5alloy were investigated by using irradiation and ultrahigh voltage electron microscopy. MeV electron irradiation was selected instead of conventional annealing to clarify the early stage of primary crystallization, which is completed during heating in conventional annealing. The dynamic observations of the Fe85Si2B8P4Cu1, Fe85Si2B12Cu1, and Fe86Si2B8P4as well as Fe76Si9B10P5amorphous alloys revealed that α-Fe nanocrystals precipitated at the irradiated region. The amorphous phase could not maintain its original structure; furthermore, α-Fe nanocrystals precipitated via irradiation-induced crystallization, which resembles thermal crystallization. The dynamic observations of the irradiation-induced nanocrystallization behavior clarified the effect of Cu and P elements on the incubation time and growth behavior of the α-Fe nanocrystals embedded in the amorphous matrix during nanocrystallization. This is the first detailed evaluation of the early stage in the nanocrystallization of an amorphous phase in NANOMET by in situ TEM observations and the MeV electron irradiation technique.