Preparation and Melting of Zr-1.0Nb Alloy

Abstract

Zirconium alloys have many applications in industry in services too harsh for stainless steels, nickel alloys or where a noteworthy improvement in service life may be achieved, by choosing zirconium alloys instead of other metals, such as high permeability to thermal neutrons and excellent corrosion resistance in nuclear reactor environments. Mixing alloying elements, such as niobium, molybdenum, tin, titanium and tantalum, with zirconium changes its physical and chemical properties, especially its resistance to corrosion. In this study, specimens of Zr-1.0Nb alloy were obtained by melting in a furnace with non-consumable electrodes in argon atmosphere. Different samples were prepared to ensure good homogeneity of the specimens. The melting procedure was tested several times to determine the parameters that ensure proper alloy handling. These parameters include the melting point of the alloys under pressure and the current in the furnace. Using the derived melting parameters and processing parameters, it has been obtained Zr-1.0Nb alloy specimens with appropriate homogeneity, as confirmed by auxiliary characterization techniques, such as optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. For these methods, the requirements for physicochemical properties in the nuclear sector were incorporated into the analyses.