Effect of Deformation Temperature and Extrusion Ratio on Microstructure and Superplastic Flow in Aluminum Matrix Composites

摘要

The effect of deformation temperature and extrusion ratio on microstructure and superplastic flow in Al composite reinforced by Si_3N_(4p) or Si_3N_(4W) was investigated. TEM micrographs and EDS analysis of the composites prepared with various reduction ratio and deformation temperature after tensile-test shows that concentration of the additive elements occurs at the interfaces and the analytical values depend on the sampling points. Out of Al composites tensile-tested at various deformation temperatures, the largest elongation is obtained at temperatures close the onset temperature for partial melting determined by DTA. Also, it can be seen average grain sizes of the matrix are reduced as increasing extrusion ratio and finally become 1-2 mu m, and that a distribution of the Si_3N_4 crystals becomes uniformly by the extrusion with high reduction ratio (<=44:1). In particular, interfacial reaction become strongly with increasing the reduction ratio.