Crystallization of Fe75Zr25 metallic glass: a two-step process involving metastable bcc-Fe and polymorphic transformation.

The crystallization process of mechanically alloyed Fe75Zr25 metallic glasses is investigated by means of both thermo-magnetization and in situ neutron powder thermo-diffraction experiments in the temperature range 300-1073 K. It was found that the crystallization takes place in a two-step process, involving firstly the appearance of metastable Fe and Fe2Zr crystalline phases between 880 K and 980 K, and a subsequent polymorphic transformation into Fe3Zr above 980 K. These findings explain the anomalous magnetization vs. temperature behaviour on heating-cooling cycles.[GRAPHICS]Contour plot of the neutron diffracted intensity (lambda = 1.28 angstrom) as a function of the Bragg diffraction angle and the temperature, (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim