Abstract
Al-4.5% Cu alloys containing Mg up to 4% were solidified under hydraulic pressure up to 3, 000kgf/cm2. These castings have an outside columnar crystal zone and a segregation zone near the center. Occurances of these zones are reduced with increasing Mg content. Although the pressured castings have dendritic structures finer than gravity castings, the finess is independent of the applied pressure. The pressure effect on the cast structure is diminished by T6-treatment. Tensile strength and particularly elongation and impact value of the pressured castings are improved with increase of the applied pressure. The alloy containing 1% Mg has the maximum tensile strength regardless of the applied pressure. More of Mg results in lowering the elongation and impact value.
