Fabrication of carbon nanotube reinforced AZ91D composite with superior mechanical properties

AZ91D alloy composites with 1.0% CNTs have been fabricated by a method combined ball milling with stirring casting. The composite was investigated using optical microscopy(OM), X-ray diffraction(XRD), Fourier transform infrared spectroscope (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM) and room temperature (RT) tensile test. The results show that CNTs were homogeneously distributed in the matrix and maintained integrated structure. The yield strength and ductility of AZ91D/CNTs composite were improved by 47.2% and 112.2%, respectively, when compared with the AZ91 alloy. The uniform distribution of CNTs and the strong interfacial bonds between CNT and the matrix are dominated to the simultaneous improvement of yield strength and ductility of the composite. In addition, the grain refinement as well as the finer β phase (Mg₁₇Al₁₂) with homogenous distribution in the matrix can also slightly assist to the enhancement of the mechanical properties of the composite.