Research On The Microstructures And Property Of ECAP For Al Powder And SiC Reinforced Al Matrix Composites

Powder metallurgy process can make the powder materials consolidation for a certain shape, size and performance of products. However, because of the production process by powder metallurgy technology is more complicated. And there will exist more pores inside product. Relative to other dense materials, the plastic deformation ability of products is weak. In the subsequent processing deformation process, there will accumulated damage. It is difficult to produce larger effective strain, thus affects the grain refinement effect and reduce strength and toughness. So it affects the mechanical properties of the material, which influences the property of material.This paper combines the characteristic of powder plastic with equal channel angular pressing (ECAP), put forward a the way called powder in tubes and vacuum hot-pressing. This paper uses the pure Al powder and the SiCp/Al composite as the experimental material. At low temperature, The experiment successfully achieves the powder particles consolidation as a high density of bulk materials and research the microstructures and property of composite materials in the process of ECAP.The evolution of microstructure after each pass of different route is observed by using optical microscope technology and transmission electron microscopy technology. Study the internal microscopic structure of sample changed before and after deformation characteristic. Then research on the mechanism of densification, the grain refinement, the interface reaction of composite material, the strengthen mechanism of composite material and the fracture mechanics of composite material.The results indicate that the densification and powder grain refinement of samples are improved after four passes by different routes of extrusion. With the accumulation of processing passes, the strength of the samples is improved significantly and the route Be has the best effect of optimization. The SiCp have a uniform distribution and refinement after 3 passes ECAP of route A and the macroscopic organization appeared periodic cracks.