Al2O3p/Al composites with compatible interface by matrix alloying

Approach to improve the wettability and adhesion between Al2O3 and Al by matrix alloying was proposed. The alloying element M will have to meet both of the following requirements: (1) It is able to reduce the surface tension of molten aluminium, gamma(M) < gamma(Al);]; (2) The oxide of M has more negative standard free energy than Al2O3, DeltaG(Mx)O(y) < DeltaG(Al2)O(3). This proposal has been proved experimentally. It has been revealed that Mg enhanced wetting dramatically. Bi, Pb, and Li promoted wetting further in addition to Mg, whereas Cu depressed infiltration. It has been found that Mg was segregated to the Al2O3/Al interface in Al2O3/6061Al composite and MgAl2O4 was formed at the interface in some case. However, Bi-and Pb-rich nanometer particles were found between or inside of reinforcement in Al2O3/6262Al composite. The mechanical properties and microstructures of 0.5 mum or 4 mum Al2O3/6061Al and 4 mum Al2O3/6262Al composites were also discussed.