Abstract

Effects of the extrusion temperature and die angle on the tensile properties of SiCIyAl composites in powder extrusion have been investigated. SiCP/Al composites were extruded at various extrusion temperatures (450, 500, 550°C) under the extrusion ratio of 25 : 1. The ram speed was maintained at 13 cm/min for all the extrusion conditions. The surface of the extruded rod appeared to be smooth without tearing at 450 and 500°C, whereas it was very rough due to tearing at 550°C. It was found that the tensile strength and elongation of the composites extruded at 500°C are greater than those of composites extruded at 450°C This is due to the easier plastic deformation of composite extruded at 500°C, compared with the composites extruded at 450°C. The effect of die angle was examined under 20=60, 120, 180°die angles at extrusion temperature of 500°C under 25:1 extrusion ratio. The tensile strength of the composites extruded with 20=60°approved to be higher than that of the composties extruded with 28 : 120 and 180°This is attributable to the higher extrusion pressure, which mixed composite powders could be densely consolidated at elevated temperatures, resulting from high friction force between billet and sliding surface of conical die.