Mechanical properties and microstructures of Al-10Mg-4.5Si matrix composites reinforced by carbon nanotubes

Abstract Carbon nanotubes (CNTs) reinforced Al-Mg-Si matrix composites were produced by powder metallurgy technique. The mechanical properties and microstructures of the composites were highly dependent on the alloy elements and the content of CNTs. Two types of precipitates were detected in the fabricated composites. It was found that the CNTs content has a series of effects on the microstructures of the fabricated composites, including densification, the dispersion condition of CNTs and interfacial bonding. Concurrently, the CNTs content also significantly affects the distribution of CNTs and oxygen content, which in turn affects the size, distribution and chemical composition of the precipitates during the composite fabrication process. Owing to the closely bonded interface, and uniform dispersion of CNTs and precipitates, the composite reinforced by 0.5 vol% CNTs achieved well balanced strength and ductility.