HIGH-STRENGTH ALUMINUM CASTING ALLOYS RESISTANT TO HOT TEARING

摘要

An aluminum casting alloy resistant to hot tearing includes, in wt%, about 4.0 to about 6.9 Zn, about 2.0 to about 3.5 Mg, about 0.6 to about 1.2 Cu, about 0.38 to about 0.57 Sc, about 0.18 to about 0.28 Zr, and the balance Al and impurities, substantially excluding Fe, Mn, and Si, said alloy characterized by a freezing range of less than about 150°C, solidus temperature above about 490°C, and eutectic phase fraction above about 5% at the late stages of solidification. The alloy is processed to form a dispersion of L12 particles inoculating fcc grains with a grain diameter of about 40 to about 60 µm, and ?'-phase precipitates enabling an ambient yield strength from about 410 MPa to about 540 MPa.