ON THE DEVELOPMENT OF MICROSTRUCTURE IN A METAL MATRIX COMPOSITE USING NANO-MATERIALS

摘要

Metal matrix composites (MMCs) containing matrices with nanometer grain sizes have been produced from pure aluminum nano-powders (particle sizes 50 - 200 nm) with SiC reinforcement (particle sizes 3-10μm). The pure Al nano-powders were produced using an exploding wire technique. Dynamic loading using a magnetic impulse technique has been used to compact the MMC to high density. The dynamic compaction process results in excellent wetting of the SiC particles by the nanocrystalline Al powders, and the retention of a nano-crystalline grain size in the MMC. Microstructural analysis of the resulting MMC showed a highly uniform distribution of SiC particles with no visible defects or pores and the absence of deleterious phases (such as A1_4C_3) at the interfaces between the aluminum nano-grains and the SiC particles. The microstructures produced and the evolution of microstructure during dynamic compaction has also been studied using TEM and found to progress in three stages. These three stages are described.