Effects of hot extrusion through a curved die on the mechanical properties of SiC p/Al composites fabricated by melt-stirring

Abstract

Metal-matrix composites (MMCs) of particulate-SiC-reinforced 6061 aluminium alloy were fabricated by the melt-stirring method. The primary MMC billets were prepared with volume fractions ranging from 0.05 to 0.20 and particle sizes ranging from 13 to 22 μm. The microstructure and mechanical properties were investigated. The MMC billets were extruded at 500°C at a constant extrusion velocity of V e=2 mm/min through a curved die. Extrusion force, particle rearrangement, microstructure and mechanical properties were examined. The mechanical properties of the primary billets were compared with those of extruded specimens. The effects of volume fraction and particle size were studied. The increase in uniformity of particle dispersion is the major reason for the improvement in reliability resulting from hot extrusion through an optimally shaped die. Young's modulus and 0.2% offset yield strength of the extruded MMCs were compared with theoretical values calculated by the Eshelby method.