Mechanical and microstructure properties of Al/CNT-Al2O3 hybrid nanocomposite produced by accumulative roll bonding process

In recent years, many attentions have been paid to decrease of the weight of components in automotive, transport and aeronautical industries, in respect of reduction of energy consumption and environmental pollution. Therefore, low-density aluminum alloys reinforced with nanoparticles especially CNT and Al2O3 have been broadly considered for application in such industries due to high strength/weight ratio. In current work, Al-CNT-Al2O3 nanocomposite was produced by accumulative roll bonding (ARB) after 6 passes. CNT-Al2O3 composite with 1wt% multi-wall carbon nanotube (MWCNT) and 2wt% nano-alumina was prepared by ball milling process. The effect of the ARB cycles on the microstructure and mechanical properties of nanocomposite were studied by field emission scanning electron microscopy images (FESEM), X-ray diffraction data, tensile and micro hardness results. FESEM images showed the uniform distribution and high quality bonding of carbon nanotubes in the matrix. X-ray diffraction analysis indicated the composite nanostructure formation with the crystal size of 53.3 nm after 6 cycles of ARB compared to 77 nm of Al after pass 11. The results obtained by the tensile and hardness tests showed that at the end of ARB process, ultimate strength was 5.9 times, and hardness was 3 times more than those of the annealed aluminum.