Magnetostrictive loss reduction through stress relief annealing in an FeNi-based metal amorphous nanocomposite

Development of high Bs Fe–Ni-based metal amorphous nanocomposite by optimization of glass-forming ability

“…Above Tc (amorphous), magnetic anisotropy in the amorphous state disappears, resulting in a sharp drop in coercivity. [1] Similar results have been reported by Kernion et al [129] in cold rolled MANC material, where annealing between Tc(amorphous) and Tx1 resulted in the lowest coercivity.…”

“…TEM diffraction results revel a mixture of BCC and FCC grains. [1] Table 8.1. A comparison of surface and bulk grain size in the samples annealed with and without applied stress.…”

“…A comparison of surface and bulk grain size in the samples annealed with and without applied stress. [1] Table 7.1. Summary of Avrami exponents for different nucleation and growth types.…”

“…Such magnetostriction induced losses have been noted for other MANC alloys. Byerly et al [1] has explored the reduction of such losses by reannealing the toroidal cores after winding. They found that reannealing above the amorphous Curie temperature but below Tx1 results in significant increase in magnetic softness, increasing permeability and reducing coercivity.…”

“…As noted in section 4.5, the coercivity of material that has been wound into a core increases significantly due to stress-induced magnetostrictive loss. The effects of reannealing to reduce magnetostrictive effects were studied by Byerly et al [1] The results below describe the effect on surface and bulk structure of the reannealing treatment. This reannealing technique and knowledge of its structural effects will be useful for the new, high Bs alloys.…”