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  Pajor, K.; Rutkowski, B.; Gondek, L; Blyskun, P.; Reehuis, M.; Wieczerzak, K.; Koziel, T.: The Scavenging Effect of Different Rare-Earth Elements in the Low-Purity Zr₅₀Cu₄₀Al₁₀ Alloy. Metallurgical and Materials Transactions A 53 (2022), p. 2902–2925

10.1007/s11661-022-06714-1
Open Accesn Version

Abstract:
Glass-forming alloys are very sensitive to oxygen contaminations. Here, the oxygen-scavenging effect of five rare-earth elements (REEs) was studied when added to the Zr50Cu40Al10 alloy, synthesized from commercially available zirconium. The effects of precise REEs additions (Y, Sc, Lu, Gd, Nd) with respect to the measured oxygen content, based on the stoichiometric relationship in the M2O3 oxide, are reported. Additionally, the influence of double and triple REE-to-oxygen ratios on the critical diameter (D-c) and other glass-forming ability (GFA) indicators were investigated. To evaluate the GFA and phase transformations during heating, differential thermal analysis was performed along with neutron diffraction. The combination of these two techniques allowed to identify crystallization products and distinguish the differences in phase transformations of low and high-oxygen-content alloys. Microstructural analysis was carried out by means of electron microscopy (SEM, STEM), supported by X-ray diffraction. The best oxygen scavengers were found to be rare earths that form cubic sesquioxides, i.e., Y, Sc, and Lu, allowing to increase D-c in the high-oxygen Zr50Cu40Al10 alloy from 2.5 mm up to 8 mm (double-stoichiometric concentration of Y-to-oxygen). Our results indicate that low-purity alloys can be easily vitrified, highlighting their potential for wide commercialization.