Reinforcing effect of multi-walled carbon nanotubes on microstructure and mechanical behavior of AA5052 composites assisted by in-situ TiC particles

Abstract

In this research, the synergistic effects of multi-walled carbon nanotubes and in-situ synthesized titanium carbide (TiC) on the mechanical performance of aluminum hybrid composites were studied. The microstructural characterization involving the influence of both titanium carbide and carbon nanotubes was investigated. The reinforcing effects of both titanium carbide and multi-walled carbon nanotubes on the micro-hardness, tensile strength, and impact strength of the composites were also investigated. The microstructures of the fractured tensile and impact test surfaces were examined through FESEM (Field Emission Scanning Electron Microscope). Clear peaks of titanium carbide (TiC) and aluminum carbide (Al4C3) were observed in the X-Ray Diffraction (XRD) analysis. The micro-hardness of the aluminum composites was significantly improved after the reinforcement with CNT and TiC. The highest ultimate tensile strength and yield strength were found with Al–9%TiC-1%MWCNT and are equal to 206.44 MPa and 136.15 MPa, respectively, whereas a 16% decrease in the impact strength of Al–9%TiC-1%MWCNT was witnessed when compared to base alloy. The effects, such as CNT pull-out, CNT bridging was seen from tensile fractography of the composites. Further, the crack initiation from the pull-out cavity was also assumed to affect the fracture mechanism. Cleavage facets were associated both with the impact and tensile fracture surfaces of the composites. With the superior mechanical properties obtained, the aluminum hybrid composite can be replaced for different structural applications.