ALUMINUM ALLOY CASTING HAVING SUPERIOR HIGH-TEMPERATURE STRENGTH AND THERMAL CONDUCTIVITY, METHOD FOR MANUFACTURING SAME, AND ALUMINUM ALLOY CASTING PISTON FOR INTERNAL COMBUSTION ENGINE

摘要

Provided is an aluminum alloy casting having superior high-temperature strength and thermal conductivity, a method for manufacturing the same, and an aluminum alloy casting piston for an internal combustion engine that uses the casting. This aluminum alloy casting has a chemical composition comprising 12.0-13.5% by mass of Si, 4.5-5.5% by mass of Cu, 0.6-1.0% by mass of Mg, 0.7-1.3% by mass of Ni, 1.15-1.25% by mass of Fe, 0.10-0.2% by mass of Ti, and 0.004-0.02% by mass of P, the remainder including Al and unavoidable impurities, and the long-axis length of Al-Fe-Si-based crystallized products is 100 μm or less on the basis of the average length of 10 crystallized products from the larger ones thereof, when observing an area of 0.2 mm2. Provided is an aluminum alloy casting piston for an internal combustion engine that comprises the aluminum alloy casting. Provided is a method for manufacturing the aluminum alloy casting in which a melt of the aluminum alloy casting having the aforementioned chemical composition is cast at a cooling speed of at least 100 degrees C/s and then subjected to an aging treatment.