Development of net-shape cast aluminium-yttrium alloy wires and their solidification structures

Abstract

Cast-aluminium-1.5–7 wt% yttrium alloy wires were produced by the heated mould (Ohno Continuous Casting) process with a typical casting speed of 1.1 m min-1. Using a 2 mm diameter channel bore and positioning the solidification front outside the mould, it was possible to cast wires of 1.6–1.9 mm diameter with uniform chemical composition along the length of the wire. Cast wires contained directionally solidified cells or dendrites of α-aluminium with metastable Al4Y and β-Al3Y phases in intercellular or interdendritic regions. At higher casting speeds (>1.1 m min-1), the predominant metastable phase was found to be Al4Y.