Crystalline Transformations in Amorphous Fe_73.5Cu₁Nb₃Si_16.5B₆ Alloy

Abstract

The crystallization behavior of the amorphous Fe 73.5 Cu 1 Nb 3 Si 16.5 B 6 alloy has been investigated by Mössbauer spectroscopy and X-ray diffractometry. Fine crystalline grains of about 10 nm diameter are produced uniformly by annealing at 550°C for 1 hour in nitrogen atmosphere. The predominant crystalline phase is assigned to the Fe-Si alloy with DO 3 structure and neither intermetallic compounds nor an amorphous phase can be recognized in the Mössbauer spectrum. The addition of 1 at% Cu to amorphous Fe-Si-B merely brings about a lowering of the crystallization temperature, while that of 3 at% Nb leads to a rise in the crystallization temperature and simultaneous formation of Fe-Si alloy and Fe 3 (Si, B). Their effects simultaneously influence the crystallization behavior in the amorphous Fe 73.5 Cu 1 Nb 3 Si 16.5 B 6 alloy, and lead to the production of Fe-Si alloy with uniform ultrafine grains. Annealing at 720°C for 1 hour gives rise to the growth of the fine grains and the formation of Fe 3 (Si, B).