The Effect of Mechanical Working on SiC Whisker-Reinforced Aluminum Alloys

摘要

The effects of mechanical working on SiC whisker-reinforced aluminum alloys were investigated. The effects of pressing, extruding, and rolling on whisker dispersion, L/D ratio, and orientation were determined by examination of polished cross sections using conventional optical microscopy and by examination of replicas with a transmission electron microscope. These results were correlated with the mechanical properties of the composite. It was found that mechanical working of the composites significantly degrades the whiskers, particularly the L/D ratio. Extrusion and rolling, however, do impart an orientation to the whiskers in the direction of working. It was also found that clumping observed in the unworked billets is carried through both the extrusion process and rolling. These SiC-rich areas apparently lead to the formation of porosity in the composites during working. The high level of mechanical properties found in the worked composites suggests that optimization of the secondary working parameters (in such a manner as to minimize whisker damage) may result in the realization of a truly unique structural material. (Author)