Metastability in Fe62.5Co6Ni7.5Zr6Nb2Cu1B15 amorphous alloy and optimisation of its magnetoelastic response

Abstract

A new metallic glass alloy characterized by high amplitude of magnetoelastic waves was synthesized. X-ray spectra evidenced the amorphous structure in the as-cast material, while differential thermal analysis confirmed the metastable initial phase and the occurrence of several crystallization peaks. The alloy shows a high difference between the glass transition and crystallization temperatures. Several heat treatments were performed and the structural relaxation effects were shown by means of the behavior of magnetization, Curie temperature and the resonant magneto-elastic wave amplitude. The strong increase of the last parameter, induced by the occurrence of the amorphous structure, is the most important result for application. Magnetic and magneto-elastic properties deteriorate if crystallization occurs, but in the optimal condition a partial nanocrystallisation may be present.