Control of Mechanical Properties of Functionally Graded Dual-Nanoparticle-Reinforced Composites

Functionally graded aluminium (Al) matrix composite materials reinforced with carbon nanotubes (CNT) and silicon carbide nanoparticles (nSiC) or nanodiamond (nD) were fabricated using a powder-metallurgical route. The nSiC and nD were not only used as a reinforcement but also as an active solid mixing agent for dispersing the CNT in the Al powder. Dual-nanoparticle-reinforced functionally graded multiple-layered composites were found to exhibit different mechanical characteristics. In particular, the hardnesses of the CNT-and nSiC-reinforced composites were dramatically increased, being up to eight times greater (330 HV) than that of bulk pure Al. In the case of the combination of the CNT and nD nanoparticles, the reinforced Al matrix composites exhibited the highest flexural strength (about 760 MPa). This functionally graded dual-nanoparticle approach could also be applied to other nanoreinforced systems, such as ceramics or complex hybrid-matrix materials. Keywords: Carbon nanotubes (CNT), nanosilicon carbide (nSiC), nanodiamond (nD), functionally graded materials (FGM), Powder metallurgy