Influence of thermal treatment on structure development and mechanical properties of amorphous Fe<inf>73.5</inf>Cu<inf>1</inf>Nb<inf>3</inf>Si <inf>15.5</inf>B<inf>7</inf> ribbon

Abstract

Ribbon-shaped amorphous samples with the stoichiometric composition Fe 73.5Cu1Nb3Si15.5B7 prepared by the melt spinning process were annealed at temperatures ranging from 693 K to 1123 K for 1 h under vacuum. In the early annealing stage, the alloy undergoes a specific nucleation process where Cu clusters precipitate from an amorphous matrix. Further heating initiates the partial crystallization of alloy forming the α-Fe-Si nanocrystallites. Subsequent Vickers hardness tests showed high values depending on the annealing temperature. It was found that the hardening process includes two stages. This behavior correlates well with results of density dislocation calculations. A crystallite size of 10 nm for the α-Fe-Si particles correlated very well with a maximum hardness of the material. © 2010 Elsevier B.V. All rights reserved.