Cold-rolling and annealing of amorphous ribbons

Cold-rolling of Fe40Ni40P14B6amorphous alloy ribbon results in a large increase in coercive force and a large decrease in magnetization in low fields. It is suggested that these changes are the result of both the sliplike structures developed by the rolling and the strain-magnetostriction induced anisotropy. On annealing the rolled ribbon to temperatures below the crystallization temperature, the magnetic properties recover to the values obtained on annealing as-cast ribbon, but higher temperatures are required. The rolled ribbon showed no evidence for structural changes in high resolution electron micrographs; x-ray and electron diffraction patterns showed no change in the width or position of the diffuse rings; and the glass and crystallization temperatures remained unchanged. However, small angle x-ray scattering showed a decrease in intensity at small angles, and stress relief measurements showed a small increase in the stress-relief rate. Both as-cast and rolled ribbons when annealed even to within a few degrees of the start of crystallization showed no change in the width or position of the diffraction peaks, and no change in the heat of crystallization, glass transition, or crystallization temperature. However, on annealing, the small angle x-ray scattering increased, and stress-relief rate decreased. The change in small angle scattering is qualitatively interpreted as being due to the removal of scattering nuclei on rolling and their development during annealing. The stress relief results are discussed in terms of changes in short-range atomic order.