Formation of cube-on-face texture {0 0 1}〈uv0〉 in a high saturation soft magnetic iron-cobalt-vanadium alloy by controlled phase-transformation γ → α

Abstract

In this investigation, the soft magnetic properties of a high saturation iron-cobalt-vanadium alloy with 17 wt% Co and 1.5 wt% V have been greatly enhanced by a special heat treatment in the γ-region, which effectively leads to the formation of a magnetically favorable strong cube-on-face texture during cooling. Based on EBSD analyses, a high degree of cube-on-face texture {001}〈uv0〉 of up to 80 % was obtained. The underlying mechanism is presumed to be a preferred surface nucleation of {001}-grains during cooling through the two-phase-region α + γ. The annealing of all samples was performed in ceramic powder. Therefore, mechanical stress is not considered the primary cause for this preferred nucleation, which should simplify the upscaling to an industrial process. As the 〈100〉 direction is the magnetic easy axis in this material system, this preferred crystal orientation goes along with very good soft magnetic properties such as a high maximum permeability µmax of 16,000, an increased induction B(160 A/cm) of 2.14 T and a reduced coercivity Hc of about 30 A/m. The core loss is reduced for frequencies up to 1 kHz. This favorable combination of properties, along with the reduced Co content, opens up new possibilities for the use of this material in electrical machines with both a high efficiency and a high power density.