Microstructure and Microstructure of Carbon Nanotube Reinforced Magnesium Matrix Composites Fabricated by Friction Stir Processing

Friction stir processing (FSP) was employed to fabricate CNTs reinforced magnesium matrix composites material. Microstructure, fracture morphology and effects of CNTs content on mechanical properties were analyzed by optical microscopy, scanning electron microscopy(SEM)and other test methods. The results show that reinforced phase refine the grains in the composite region; the microhardness of the composite region was increased as the CNTs content increasing, while the tensile strength of the composite material was increase first then decrease as the content increasing. Fracture mode of the composite was changed from mixed fracture to brittle fracture; reunion of the CNTs is especially notable as the content over 7.1%. The fracture interface of the reunion region is smooth and that is the very place where crack begin that reducing the tensile strength.