Eutectic or hypereutectic aluminum-silicon alloy product for semisolid forming in forging and pressure injection operations

摘要

The Al-Si alloy contains (in weight %) 10-30% Si and optionally = 10% copper, = 3% Mg, = 2% Mn, = 2% Fe, = 4% Ni, = 3% Co and = 0.5% each of and 1% total of other elements. The product has a microstructure consisting of primary silicon, aluminum dendrites of size less than 4 mm, and a eutectic comprising grains of eutectic silicon and grains of eutectic aluminum of size below 4 mm. The product contains 0.002-0.05% P, 0.005-0.2% B, preferably 0.01-0.05% B, and at least 0.005% non-associated boron in the form of an intermetallic compound with at least one of Ti, Zr, Mn or V. An Independent claim is given for a process for manufacture of the product, comprising adding to a liquid alloy used for manufacture of the product an amount of boron in excess of that necessary for the elimination of impurities. Boron is introduced in the form of a master alloy of AlB, SiB or AlSiB or a fluoroborate-based flux into the molten alloy.