Influence of Cu admixtures on the crystallization of amorphous Fe75Si9B16

The crystallization of the amorphous alloys Fe75-xCuxSi9B16 (x less than or equal to 4) is completed in three stages: (a) dendritic growth of bcc Fe[S i,Cu], (b) eutectic crystallization of bcc Fe[Si,Cu] + bet Fe3B and, finall y, (c) formation of bet Fe3B. The metastable compound Fe3B formed during th e second and third stages is eventually dissolved into bcc Fe and bet Fe3B. As Cu atoms replace Fe atoms, the kinetics of the whole process is modifie d because of microsegregation: the first stage is decelerated, the second i s accelerated, and the third is accelerated up to 2 at% Cu, but is decelera ted at higher concentrations. (C) 2000 Elsevier Science Ltd. All rights res erved.