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

• Published in: Physica status solidi. PSS-RRL. Rapid research letters 2009-01, Vol.3 (1), p.28-30
• Main Authors: Gorria, Pedro, Garitaonandia, Joseba S., Pérez, María J., Blanco, Jesús A., Campo, Javier
• Format: Article
• Language: English
• Subjects: 61.05.fm; 64.70.pe; 75.50.Bb; 81.20.Ev; 81.30.Hd; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Growth from solid phases (including multiphase diffusion and recrystallization); Materials science; Methods of crystal growth; physics of crystal growth; Physics
• ISSN: 1862-6254; 1862-6270
• DOI: 10.1002/pssr.200802241

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. Contour plot of the neutron diffracted intensity (λ = 1.28 Å) as a function of the Bragg diffraction angle and the temperature. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) Combined thermo‐magnetization measurements and in situ neutron powder thermo‐diffraction experiments in the temperature range 300–1073 K provide clear evidence of a complex two‐step crystallization process in Fe75Zr25 metallic glass, instead of the simple expected transformation into Fe3Zr crystalline phase. The first step gives rise to the formation of bcc‐Fe and Fe2Zr. Further heating provokes the polymorphic transformation into Fe3Zr.