A method for grain refinement of high-strength cast aluminum alloys comprising

摘要

A method of casting an aluminum base alloy which comprises providing a melt of an aluminum base alloy comprised of 4 to less than 5 wt.% Cu, max. 0.1 wt.% Mn, 0.15 to 0.55 wt.% Mg, max. 0.4 wt.% Si, max. 0.2 wt.% Zn, up to 0.4 wt.% Fe, the balance comprised of aluminum, incidental elements and impurities. The dissolved Ti in the melt is maintained in the range of about 0.005 to 0.05 wt.% to improve the resistance of the alloy to hot cracking. A nucleating agent added to the melt to provide an undissolved nucleating agent therein, in the range of 0.002 to 0.1 wt.% for grain refining. The said alloy is solidified to provide a cast product having a grain size of less than 125 microns and free of hot cracks. The figure illustrates a scale drawing of the casting used to evaluate the new grain refining practice and locations where cracks were observed (1, 2, 3, 4).