アルミナ／アルミニウム粉末複合材料の機械的性質と据込み加工性

Abstract

Alumina/aluminum composites were fabricated by sintering or extruding subsequently mixed powder of a pure aluminum and an alumina. Some mechanical properties, a critical reduction in height in upsetting and changes in the properties after upsetting were investigated for the composites. Although a pure aluminum fabricated from the powder had higher strength than a cast aluminum because of so-called SAP effect, a good wear resistance was obtained only in a composite specimen containing alumina particles. The critical reduction in upsetting at room temperature and 200°C for an extruded billet withou talumina particles was higher than that of a sintered billet. However, in upsetting of billets containing alumina particles the critical reduction, which increased with an upsetting temperature, was little affected by the fabrication process. In upsetting beyond the critical reduction, fine vertical and large zigzag cracks appeared on the surfaces of the billets without and with alumina particles. Before upsetting the hardness of billet extruded at 200°C was higher than that of others, while after upsetting the hardness values of both billets extruded at 200°C and 450°C were almost the same.