On the role of matrix microstructure on Al/SiC nanocomposites

Abstract- Aluminum matrix composites (AMCs) reinforced with nanometeric particles exhibit superior mechanical properties as compared with those reinforced with coarser ones. This effect can be attributed to (i) the presence of nano-sized particles enhancing the mechanical properties mainly due to Orowan strengthening mechanism and (ii) the refined microstructure of the matrix alloy developed during processing of such composites. Although the first effect has been extensively discussed in the literature, the second one has not yet been investigated. In the present study AMCs reinforced with 1,2 and 3 vol.% nano-sized SiC particles were produced via mechanical milling and hot extrusion. The microstructure and hardness of these composites were compared with those produced using as-received Al powders to clarify the role or matrix microstructure in hardness of Al/SiC nanocomposites. It was concluded that the matrix nano-crystals developed during mechanical milling has substantial effect on improving the hardness of composites. Keywords - , , , .