SOLID-STATE REACTION BETWEEN CRYSTALLINE NICKEL AND AMORPHOUS FE78SI12B10 POWDERS DURING MECHANICAL MILLING

The solid-state reaction between crystalline nickel and pulverized mel t-spun amorphous Fe78Si12B10 powders during mechanical milling has bee n investigated. For the powder mixtures with low nickel content (less- than-or-equal-to 30 at%), the reaction results in the production of a new amorphous phase. For the powder mixture with a high nickel content (up to 50 at%), crystalline gamma(Fe, Ni) and new amorphous phases ar e obtained. During the milling process, nickel atoms can dissolve in t he amorphous matrix by diffusion due to severe deformation. The existe nce of ''free volume'' in the melt-spun amorphous phase may favour the diffusion of nickel atoms. At the same time, the elemental atoms (suc h as iron) in the amorphous phase may also dissolve into the nickel ma trix. The amorphization between the amorphous and crystalline phases i s attributed to the asymmetry of interdiffusion of the atoms in differ ent matrices.