Extrusion characteristics of spray-formed AC9A aluminum alloy

JIS-AC9A alloy was spray-formed and the microstructures between spray-formed and conventional cast AC9A alloys were compared. Spray-formed AC9A billets were then extruded into bars under two different conditions of reduction ratio, preheating temperature and die temperature. The morphologies of extruded bars were analyzed to reveal the surface defects. The morphology, size and distribution of Si particles after extrusion were compared along different directions for various extrusion conditions. The porosity level after extrusion was compared for various extrusion conditions. The formation and propagation of surface crack were analyzed and studied. The relationships among surface crack length, its penetration depth and extrusion temperature were investigated and an empirical relationships was found to describe the relationships.