Mechanically induced crystallization of an amorphous CoFeZrB alloy

Abstract

The short-time (12 h) ball milling of the amorphous Co56Fe 16Zr8B20 (at. %) alloy resulted in the formation of bcc-Fe nanocrystals embedded in an amorphous matrix. X-ray diffraction (XRD) using synchrotron radiation, differential scanning calorimetry (DSC), vibrating sample magnetometery (VSM), and the Faraday magnetic balance experiments were used to characterize the materials. XRD and DSC show that the fraction of crystallized bcc-Fe gradually increases with the milling time. The VSM measurements confirm the structure observations showing that the saturation magnetization increases with the milling time as the fraction of crystallized bcc-Fe increases. After 12 h of milling, the powder sample exhibited a Curie temperature of the amorphous phase TCam, which is approximately 55 K higher compared to the as-quenched ribbon (TCam=601 K). Thermomagnetic measurements of heat-treated ribbons suggest that such an increase in TCam is not only due to temperature rises during the milling but may also be attributed to the combination of mechanical and thermal effects connected with the nature of milling. © 2006 American Institute of Physics.