The effect of Co and Sn on Zr-Nb alloys for high temperature application
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MRS Advances © 2018 Materials Research Society DOI: 10.1557/adv.2018.500
The effect of Co and Sn on Zr-Nb alloys for high temperature application M.M MALEBATI, P.E. NGOEPE and H.R. CHAUKE 1
Materials Modelling Centre, University of Limpopo, Private Bag X 1106, Sovenga, 0727, South Africa
Corresponding author: M.M Malebati, email:[email protected]
Abstract
Zirconium has attracted a lot of attention recently due to its distinctive properties that make it suitable for extensive applications in the nuclear power and chemical industry. Zirconium and its alloys are undergoing long-term development as promising materials for the nuclear industry and power engineering. Recently, advanced Zr-based alloys are aimed for service in more severe operating conditions such as higher burn-up, increased operation temperature, and high-PH operation. In this work we observe the temperature dependence of Zr 50Nb50, Zr78Nb22, Zr78Nb19Co3 and Zr50Nb49Sn1. It was observed that ternary additions with small atomic percentages of Co and Sn have significant impact on Zr-Nb alloy; and their elastic properties showed a possible enhancement on high temperature applications and physical strength.
INTRODUCTION Zirconium is a commercially available refractory metal with excellent corrosion resistance, good mechanical properties and very low thermal neutron cross section [1]. Zirconium alloys have superior thermal properties as compared to other traditional materials in consideration for nuclear and industrial applications [2]. Most of these Zr alloys contains Nb as the major alloying element, which is recommended for developing new fuel cladding materials since it is an effective strengthening element [3, 4]. Nuclear reactors mostly suffer failure and performance deterioration depending on the material used. A variety of alloying elements has been explored in order to improve the resistance to creep, corrosion and yield strength of a cladding material Sn, Sc, Sb, Fe and Cr etc [5, 6]. ZrNb alloys are being developed to improve the economy of nuclear plants. Most of
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the developing alloys are found to have higher Nb and lower Sn contents (in Zr-Sn alloys) in order to improve corrosion resistance [7]. Apart from the binary Zr alloys, theoretical and experimental attempts have been performed to better the performance in the industries using ternary systems such as Zr-Nb-Fe [8] and Zr-Nb-Sn(O) [9]. It was reported previously that alloying zirconium-based system with Co and Nb could improve the thermodynamic and mechanical properties of zirconium alloys [10]. In this paper, a self-consistent DFT was used to investigate the effect of Co and Sn addition on the Zr-Nb system. The choice of Sn is based on its ability to enhance the cladding properties for industrial application [11]. We employ the V
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