| abstract |
Aluminum alloys and castings are provided that have excellent practical fatiguenresistances. The alloy includes, based upon 100 mass %, 4-12 mass % of Si, less than 0.2nmass % of Cu, 0.1-0.5 mass % of Mg, 0.2-3.0 mass % of Ni, 0.1-0.7 mass % of Fe, 0.15-0.3nmass % of Ti, and the balance of aluminum (Al) and impurities. The alloy has anmetallographic structure, which includes a matrix phase primarily of α-Al and a skeletonnphase crystallizing around the matrix phase in a network shape. The matrix phase isnstrengthened by precipitates containing Mg. Because of the strengthened matrix phase,nand the skeleton phase that surrounds it, the castings have high strength, high fatiguenstrength, and high thermo-mechanical fatigue resistance. |