| 摘要 |
PROBLEM TO BE SOLVED: To provide an aluminum alloy diecast molding in which permanent growth can be suppressed even without performing heat treatment for stabilization. SOLUTION: In the aluminum alloy diecast molding having reduced permanent growth comprises, by mass, 1.5 to 4.0% Cu and 7.5 to 12% Si, Ca and/or misch metal having a relatively large atomic radius is incorporated, so that the lattice constant of anαphase directly after casting is controlled to the range of 4.0485 to 4.0500Å, or, the cooling rate on cooling is made slow, so that the solid solution content in theαphase of Si and/or Cu having a relatively small atomic radius is reduced as possible. For solid solution strengthening,≤2.0% Zn can be incorporated therein. After long time heating, the generation rate of permanent growth as expansion more than linear expansion caused by the precipitation of Si and/or Cu from theαphase can be reduced as possible. COPYRIGHT: (C)2004,JPO&NCIPI
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