Mechanical solid state mixing for synthesizing of SiC p/Al nanocomposites

Abstract

High-energy ball milling was successfully employed to fabricate the metal matrix composite (MMC) of Al reinforced with SiC particulate (SiC p) with distinct nanocrystalline characteristics. The powders of the end-products (86 ks of milling time) of the mechanically-mixed nanocomposites SiC x Al 100− x ( x=2, 5, 7, 10 vol. %) that have spherical-like morphology (less than 0.5 μm in diameter) were consolidated into bulk compacts, using a plasma activated sintering method. Density measurements show that this consolidation step leads to the formation of fully dense bulk samples. Moreover, the consolidated SiC x Al 100− x samples reveal a nanocrystalline structure with a homogeneous reinforcement distribution of SiC p in the Al matrix. Reactive products, i.e. Al 4C 3 and Si, could not be detected on the interfaces between the reinforcement and the matrix in both mechanically mixed powders and consolidated samples. The mechanically mixed powders and consolidated compacts have been characterized by means of X-ray diffraction, scanning and transmission electron microscopes, optical metallography and chemical analyses. The hardness and some mechanical properties of SiC p/Al have been determined as a function of SiC p content.