effect of extrusion process on the microstructure and strength of al6061-sic composite

al-sic composites are among the most demanding metal matrix composites due to their excellent strength, good ductility, good corrosion resistance, low coefficient of thermal expansion and reasonable price. manufacturing of cast metal matrix composites usually involves some problems such as inhomogeneous distribution of the particles due to poor wetability of ceramics to molten alloys, porosity and formation of particle-void clusters. thus it seems necessary to utilize secondary processes for these materials in order to obtain suitable properties. in this research al6061 composites reinforced with 10 volume percent sic particles of 48?m average size were produced by the stir casting method and effect of extrusion process on the microstructure and strength of these materials was investigated. results showed that the average particle size and porosity of the composite samples decreased after extrusion. moreover, tensile strength of the composite increased by increasing the extrusion temperature and/or the extrusion ratio since the pores in the microstructure diminished and the interface bonding was improved.