Casting an aluminum alloy, an aluminum alloy casting, and a manufacturing method thereof

(Assignment) To provide an aluminum alloy casting with excellent strength, fatigue resistance, etc. (Solution) An aluminum alloy casting according to the present invention includes 4-12% Si, 1.0-3.0% Cu, 0.2-0.6% Mg, 0.2-3% Ni, o.1-0.7% Fe, 0.1-0.3% Ti, 0.03-0. 5% Zr, balance Al and inevitable impurities, when the entirety is taken as 100% by mass and has a metallographic structure, comprising a base phase mainly consisting of ±-Al, a skeleton phase which is crystallized to surround the base phase in a network configuration, and the first and second precipitation phases which are precipitated in the base phase and have different particle sizes. This aluminum alloy casting has an excellent thermal fatigue strength as well as high strength and high fatigue strength as a base material.