Structural relaxation and associated ΛH effect in the Fe‒Cu‒Nb‒Si‒B system

Abstract

Abstract The microstructural evolution from the amorphous to nanocrystalline phase in the Fe73·5Cu1Nb3Si13·5B9 alloy produced by planar flow casting was studied by performing Young's modulus, internal friction and initial susceptibility measurements against temperature on as-cast ribbons and on samples submitted to selected furnace heating treatments. Moreover, the room-temperature magnetoelastic behaviour in the as-prepared ribbons and in samples annealed in the 570–850 K range was investigated through the analysis of the ΛE effect. The results indicate that a structural relaxation process of the amorphous phase occurs starting from 450-500 K. In particular, a strong magnetoelastic response observed in samples annealed in the 710–745 K range, namely at temperatures very close to the nanocrystallization temperature (760–770 K), suggests an increase in the saturation magnetostriction with respect to the as-cast alloy, connected with atomic rearrangements causing a compositional fluctuation in the amorphous...