Brunswick Corporation
Hypereutectic aluminum-silicon cast alloys having unique microstructure

Abstract:

A hypereutectic aluminum silicon high pressure die cast alloys is disclosed herein having 16% to 23% by weight silicon, 0.01% to 1.5% by weight iron, 0.01% to 0.6% by weight manganese, 0.01% to 1.3% by weight magnesium, 0.05% to 0.20% by weight strontium and the balance aluminum. The iron constituency may me modified to 0.01% to 0.7% by weight iron, or 0.01% to 0.2% by weight iron. The manganese constituency may be modified to 0.01% to 0.5% by weight manganese. The strontium constituency may be modified to 0.05% to 0.1% by weight strontium. The exhibits an elongation of at least 2%, an average ultimate tensile strength of greater than 250 MPa, and yield strength of greater than 200 MPa. The microstructure has a volume fraction of primary silicon at greater than 10% and a volume fraction of modified aluminum-silicon eutectic at 45% to 90%.