Effect of Carbon Nanotube (CNT) Content on the Hardness, Wear Resistance and Thermal Expansion of In-Situ Reduced Graphene Oxide (rGO)-Reinforced Aluminum Matrix Composites

Abstract

Aluminum matrix composites reinforced with reduced graphene oxide (rGO) and hybrid of carbon nanotube (CNT) and rGO are fabricated by solution coating powder metallurgy process. The hardness, wear resistance and coefficient of thermal expansion (CTE) of the reinforced aluminum composites and the associated microstructural changes with rGO range (0.2-0.6 wt. %) and hybrids of 0.2 wt. % CNT-rGO at different ratios have been investigated. The intensive microstructural observations show that rGO is adsorbed on Al particles and uniformly distributed in the Al matrix composites. The hardness values of the composites increase significantly with rGO reinforcement exhibiting the maximum hardness at 0.4 wt. % rGO. Compared with the hybrid composites CNT-rGO/Al counterparts fabricated by the same route and wt. percent of 0.2, the hardness values in the hybrid CNT-rGO increase considerably. Similar to the hardness, the results of wear tests also exhibit corresponding variation in the values of the wear rates. The improvement in the wear resistance of the hybrid CNT-rGO/Al composite is pronounced in this work. Whereas the rGO reinforcements decrease significantly the wear rate of the aluminum-base by 98%, the wear resistance of the corresponding hybrid CNT-rGO is significantly higher than that of the preceding composites. Maximum CTE reduction of 28% was recorded for hybrid CNT-rGO (1:1) reinforced composite.

Mechanical and Thermal Evaluation of Aluminum Hybrid Nanocomposite Reinforced with Alumina and Graphene Oxide

“…In another study, an increase in GO has yielded an increase in the hardness of Al-GO composites up to 0.4 wt.% GO, with a maximum increase of 163.8%, but the hardness has declined upon increasing the GO reinforcement to 0.6 wt.%. The wear rate of Al-GO composites is found to reduce with increasing GO content [ 31 ]. However, graphene is prone to forming aluminum carbide during the processing of Al-graphene composites, which lowers the hardness and tensile strength.…”

Poly(L-lactic acid) Reinforced with Hydroxyapatite and Tungsten Disulfide Nanotubes

“…The optimum hardness value was obtained for the films containing PLLA with 40 wt% HA NPs and 0.5 wt% INT-WS 2 with 38.5 HV, a value that is two times higher than the hardness of the pure PLLA film. It can be deduced that a small number of nanotubes added to the matrix can bridge the gap between the HA nanoparticles creating a uniform network of hardening material [49,50]. Beyond the optimal concentration of 0.5 wt%, the nanotubes have a deleterious effect on the hardness of the nanocomposite, likely due to agglomeration [51].…”

Microstructure, hardness, and tribology properties of the (Cu/MoS2)/graphene nanocomposite via the electroless deposition and powder metallurgy technique

“…To get a homogeneous distribution for reinforcements and good interfacial bonding at a temperature less than the melting point temperature of the matrix as well as minimize raw materials consumption and near net shape character, the powder metallurgy technique was the best choice. 18–21…”

“…To get a homogeneous distribution for reinforcements and good interfacial bonding at a temperature less than the melting point temperature of the matrix as well as minimize raw materials consumption and near net shape character, the powder metallurgy technique was the best choice. [18][19][20][21] This experimental work concentrates on studying the influence of the heating rate on the bulk density of the Cu-MoS 2 /GNs nanocomposites by the powder metallurgy method. Also, studies the effect of the graphene weight percentage on the microstructure, hardness, wear rate, wear mechanism, and the COF.…”