The effect of surface composite layer fabricated via friction stir processing on ductility and hardness of Al alloys

In this research the effects of surface composite layer produced by friction stir processing (FSP) on microstructure and ductility of Al alloys were investigated. Metallography results revealed that fabricated surface composite layer structure (SCLs) improved hardness of base metal and grain refinement. Also using SiC particles caused to produce finer grains which can be attributed to pinning effect of SiC particles in prevention of grain growth of the Al matrix SCLs. In addition, SCLs hardness was increased due to grain refinement and existence of rigid SiC particles. Bending test results illustrated that ductility decreases however, with increasing FSP without using SiC particles and increasing the passes ductility was improved

Keywords:

Friction stir processing , Ductility , Surface composite layer , Ultrafine grain