PRODUCTION OF SUPERPLASTIC HYPEREUTECTIC ALUMINUM-SILICON POWDER METALLURGY ALLOY

摘要

PURPOSE: To produce superplastic hypereutectic Al-Si powder metallurgy alloy excellent in wear resistance, light weight characteristics, low thermal expansion coefficient, and mechanical strength by forming a rapidly solidified powder of Al-Si alloy of specific composition at a high cooling velocity and then solidifying and forming this rapidly solidified powder by means of hot extrusion in the air. ;CONSTITUTION: A rapidly solidified powder of Al-Si alloy of hypereutectic composition in which 15-30wt.% Si is contained in Al as matrix and also 1.5-4% Cu and 0.7-2% Mg are further contained, if necessary, as matrix strengthening components is produced at ≥10°C/sec cooling rate. This powder is used as a starting material and subjected, after hot compaction in vacuum if necessary, to hot extrusion in the air at about 300-400°C at ≥about 50 extrusion ratio. Then, if necessary, heat treatment such as T6 treatment is applied to strengthen the matrix. By this method, superplastic characteristics can be produced in the powder metallurgy alloy.;COPYRIGHT: (C)1996,JPO