Microstructure and corrosion properties of 5A06 aluminum matrix surface composite fabricated by friction stir processing

A novel aluminum matrix surface composite added with an Al-based amorphous was fabricated by friction stir processing (FSP). The surface composite region shows the obvious sandwich structure. It is considered to be a combination of the base metal and the amorphous strip via FSP. A large number of ultrafine-grained structures, which were composed of the alpha-Al and alpha-Al amorphous structures can be observed in the surface composite. The average hardness of the surface composite is about HV97, higher than the base metal, which is about HV80. The as-received sample has the highest resistance to corrosion in a salt solution. The surface composite added with the amorphous strip had lower icorr, corrosion current density, and higher passivation current than the surface composite not added with the amorphous strip.