Characteristics of Hypoeutectic Cu–Zr Alloy Rods Manufactured by Vertically Upwards Continuous Casting

Abstract

This study applied a vertically upwards continuous casting (VUCC) mass-production method to the pilot-scale production of hypoeutectic Cu–xZr (x = 0.25–5 at%) alloy rods. The microstructures of these VUCC rods were investigated and compared with those of rods produced by copper mold casting (CMC). In addition, the wire-drawing ability of the VUCC rods was examined, and the adaptability of the VUCC method to the mass production of hypoeutectic Cu–Zr alloys was fully investigated. The results show that VUCC provides a higher rate of cooling than CMC, with the resulting dendritic microstructure expected to contribute to its arm-spacing refinement. Furthermore, the VUCC rods exhibit good wire-drawing ability. The ultimate tensile strength, total strain to fracture, and electrical conductivity of Cu–2.5Zr (at%) alloy wires with diameter of 13.8 μm drawn from a VUCC rod are 1882 ± 28 MPa, 2.2 ± 0.2%, and 21% IACS (i.e. 21% of the International Annealed Copper Standard conductivity of annealed copper), respectively. The results suggest that VUCC has good potential to be adapted for mass production of hypoeutectic Cu–Zr alloy rods.