METAL TREATMENT TO ELIMINATE HOT TEAR DEFECTS IN LOW SILICON ALUMINUM ALLOYS

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An aluminum alloy and a method of casting. At least one of zirconium, scandium, a nucleating agent selected from the group consisting of metal carbides, aluminides and borides, and rare earth elements are added to the alloy while in the molten state such that upon solidification, the cast alloy exhibits improved hot tear resistance. In a particular form, the nucleating agent may be titanium diboride for grain refining. Other agents that can be used for grain refining include scandium, zirconium, silicon, silver and one or more rare earth elements. In the case of rare earth elements, mischmetal may be used as a precursor. Combinations of titanium diboride and at least one other agent are especially effective in reducing the incidence of hot tearing in products cast from the modified aluminum alloy.