Beata Gracz

The efficiency analysis of grain refinement in high-zinc aluminium alloys with Ti-containing master alloy

ABSTRACT The paper concerns double high-zinc aluminium alloys inoculated with master alloys containing titan and comprises research on the influence of inoculation on grain refinement. Most aluminium alloys before being cast have relatively low strength properties and therefore a series of treatments are applied in order to improve these properties. One of the treatments is the grain fragmentation process, called grain refinement treatment that allows to improve material properties of alloy, improve the feeding properties during the casting solidification, as well as to obtain more robust machinability of casting. Al alloy with 20wt% Zn (AlZn20) was tested, inoculated with the addition of traditional master alloy AlTi3C0.15 before casting to the sand mould. The results obtained during the studies show nucleating activity of the master alloy, proved by reduced overcooling and recalescence on cooling curves. Additionally, the role of titanium in this process is explained.