Abstract: A method of casting an aluminum alloy is provided. The method includes casting a master aluminum alloy having a trisilanol phenyl polyhedral oligomeric silsesquioxanes (TSP) modifier into an ingot and adding the master aluminum alloy ingot into a molten base aluminum alloy to form a modified aluminum alloy. The modified aluminum alloy is heated for a period of time and then cast into a cast component. A variation of the method includes mixing a powdered aluminum alloy with a powdered TSP and pressing the mixture of powdered TSP and powdered aluminum alloy into a compacted preform prior to casting the master aluminum alloy. The compacted preform is melted during the step of casting the master aluminum alloy.

Abstract: The invention relates to an improved cast Al alloy designed to provide an accelerated response to heat treatment; specifically, the alloy's response to thermal growth during aging is accelerated, leading to a dimensionally more stable casting. This improvement is achieved by the addition of trace amounts of Sn, In, Ge or Cd to an Al—Si—Cu cast alloy. The improved alloy has particular application for cast Al engine blocks and cylinder heads.