Microstructure and mechanical properties of carbon nanotube reinforced magnesium matrix composites by powder metallurgy

Because carbon nanotubes(CNTs)possess superior physical properties and mechanical properties,they are considered as one of the ideal reinforcement for metal matrix composites.It is,however,obvious that segregation of CNTs due to their strong van der Waals forces will produce material defects,decreasing the material properties.So it is a important research topic to obtain the composites with CNTs dispersed well.CNTs and pure magesium powders were mixed thoroughly either by ball milling or in the isopropanol(IPA)in the present study, Mg powder with CNTs were fabricated into CNTs reinforced Mg matrix composites with cold pressing and sintering.The microstructure and mechanical properties of the composites with the mass fraction of 1% CNTs were analyze contrastively by optical microscope,SEM,XRD and hardness tester.SEM results show that CNTs are dispersed by IPA on the surface of Mg powders and the minority of them are aggregated.XRS results show that a small amount of MgO exsits in the sintered composites.The hardness of Mg/CNT composites by IPA and by ball milling is improved with 18%and 0%compared to that of pure Mg without CNTs.