MANUFACTURE OF SUPERPLASTICITY SILICON NITRIDE WHISKER REINFORCED ALUMINUM ALLOY COMPOSITE

摘要

PURPOSE:To manufacture the Al alloy composite in which superplastic deformation is executable by subjecting uniformly mixed powder of alpha-type silicon nitride whiskers and 6000-series Al alloy powder having specified grain size to pressure sintering in vacuum and thereafter subjecting the sintered body to repressing, hot extruding and heat treatment in succession. CONSTITUTION:alpha-type or beta-type silicon nitride whiskers and 6000-series or 7000-series Al alloy powder having =44mu grain size are charged to an organic solvent such as ethanol by prescribed ratio, to which ultrasonic vibration is applied, and uniform mixing is executed. Next, the organic solvent is vaporized away, and the remaining mixed powder is held, e.g. at about 600 deg.C under about 200MPa pressure for about 20min and is subjected to pressure sintering. Furthermore, the sintered body is subjected to repressing, e.g. at about 600 deg.C under about 400MPa pressure for about 20min in the air, is subjected to hot extruding at about 500 deg.C at about 44 extrusion ratio and is subjected to T6 heat treatment. In this way, the silicon nitride whisker reinforced Al alloy composite executable of superplastic deformation can be obtd.