DEVELOPMENT OF NET-SHAPE CAST ALUMINUM-YTTRIUM ALLOY WIRES AND THEIR SOLIDIFICATION STRUCTURES

Cast-aluminium-1.5-7 wt % yttrium alloy wires were produced by the hea ted mould (Ohno Continuous Casting) process with a typical casting spe ed of 1.1 m min(-1). Using a 2 mm diameter channel bore and positionin g the solidification front outside the mould, it was possible to cast wires of 1.6-1.9 mm diameter with uniform chemical composition along t he length of the wire. Cast wires contained directionally solidified c ells or dendrites of cc-aluminium with metastable Al4Y and beta-Al3Y p hases in intercellular or interdendritic regions. At higher casting sp eeds ( > 1.1 m min(-1)), the predominant metastable phase was found to be Al4Y.