Local crystallization induced in Fe-based amorphous alloys by swift heavy projectiles

Abstract

We report the effect of the high density of electronic excitation deposited along the path of swift heavy ions in various amorphous alloys. The samples were irradiated at low temperature with GeV Pb ions up to fluences of 1×1011 to 2.3×1013cm−2. The formation of nanocrystalline phases was observed by transmission electron microscopy in the FINEMET-like Fe73.5Nb4.5Cr5Cu1B16 alloy and in the NANOPERM ternary Fe90Zr7B3 glassy systems but not in the Fe80.5Nb7B12.5 alloy. The crystallization phenomenon was interpreted in terms of the relaxation of the high level of energy deposited in electronic excitations along the path of Pb ions in the target, which induce radial pressure waves in the vicinity of the projectile trajectories. These mechanical stresses destabilize the amorphous structure and induce nanocrystallization.