Crystallization of CoFeSiB metallic glass induced by long-time ball milling

Abstract Milling up to 800 h causes amorphous Co 70.3 Fe 4.7 Si 10 B 15 alloy, prepared in the form of thin ribbon, to partially crystallize thus forming a powder material consisting of an amorphous phase and fcc-Co nanocrystals with an average grain size of about 10 nm. A gradual increase of the nanocrystalline fcc-Co fraction, produced by ball milling, was detected. Prolonged milling results in destabilization of the fcc-Co phase and oxidation of the powder material (presence of CoO phase after 1500 h of milling). The thermal stability studies of as-quenched and milled Co 70.3 Fe 4.7 Si 10 B 15 alloy emphasized a two step crystallization behavior. During the first crystallization event, cobalt rich phases, i.e., fcc-Co and hcp-Co crystallize, whereas after the second crystallization event, Co 2 B and Co 2 Si are formed.