Friction stir welding (FSW) has been generating interest in association with friction stir processing (FSP), a new technique that employs FSW tooling. In a recent study, this author investigated the excellent fluidity of aluminum alloy with FSP for creating metal matrix composites (MMCs) by the local dispersion of aluminum oxide particulate in aluminum alloy. In this study, two novel methods of property modifications, local reinforcement and local metallic foam of 6061 aluminum alloy by FSP, are proposed. Tungsten carbide (WC) particulate and SiC whisker reinforced aluminum alloy plate are produced for local reinforcement of 6061Al by FSP. FSP can also produce local aluminum composites containing titanium hydride (TiH2) particles. These results, which indicate the feasibility of producing local metallic foam by FSP, are discussed in terms of microstructure and mechanical properties.