Al (Zn)-4Cu/Al2O3 in-situ metal matrix composite synthesized by displacement reactions

Different approaches have been investigated to synthesize Al(Zn)-4Cu/Al2O3 composites by displacement reactions involving Al, ZnO and CuO. The reactions have been performed either by mechanosynthesis, exothermic dispersion or a combined mechanical and thermal activation process. Differential thermal analysis, X-ray diffraction and scanning electron microscopy have been used to study the various reaction mechanisms and transformations. High-energy ball milling of the powder modifies the reactivity of the system. A milling treatment not only reduces the reaction temperature, but can also induces a different reaction path. It is reported here that an appropriate mechanical-thermal treatment leads to the synthesis of an Al(Zn)-4Cu/Al2O3 composite. The hardness and wear resistance of the in situ composites increase with the milling time. (C) 2007 Elsevier B.V All rights reserved.