Fabrication of A356 aluminum alloy matrix composite with CNTs/Al2O3 hybrid reinforcements

Since the discovery of carbon nanotubes (CNTs), many interesting studies on composites with CNTs have been performed. However, it is extremely difficult to disperse CNTs in metal melts due to their poor wettability and large surface-to-volume ratio. The array of short fibers in a preform could be used to disperse the CNTs in the matrix. The use of hybrid reinforcement is required to solve the dispersion problems. Multi-wall carbon nanotube (MWCNT)/Al2O3sf preform-based aluminum hybrid composites were studied. A high temperature compression test was performed to evaluate mechanical properties and workability. In addition, dispersion of the carbon fiber was investigated using a hardness test. The compressive strengths of hybrid metal matrix composites (MMCs) increased with increasing Al2O3 fraction. However, the compressive strengths were not necessarily proportional to the CNT fraction. Excessive CNTs adversely affected the material due to agglomeration or poor wettability with the matrix.