Production of Al–Zr master alloy starting from ZrO2

Abstract

Abstract A process involving in-situ reduction of zirconium oxide with excess aluminum in the presence of cryolite flux has been developed for the preparation of a Al–Zr master alloy. The findings of this process are reproduced on doubling the batch size, and pilot scale results indicated viability of the process for commercial scale exploitation. It has been found possible to produce Al–5%Zr alloy in batches of 20 kg with over 92% yield on holding the charge for 1 h in the temperature range of 1100–1200°C. The addition of the master alloy to pure aluminum to the extent of 0.3%Zr in Al, effectively reduced the grain size from 1100 to 163 μm and correspondingly improved the ultimate tensile strength (UTS) of Al. The present process is found to have an edge over the conventional process of direct alloying.