Effect of Multi-Walled Carbon Nanotubes and Carbon Fiber Reinforcements on the Mechanical and Tribological Behavior of Hybrid Mg-AZ91D Nanocomposites

Abstract

Magnesium matrix composites are extensively used in automotive and structural applications due to their low density, high strength, and wear-resistant properties. To reach the scope of industry needs, research is carried out regarding enhancing the mechanical and tribological behavior of the magnesium composites by reinforcing the nano-sized reinforcements. In the present work, research has been carried out to enhance the properties of the magnesium AZ91D hybrid composite by reinforcing carbon fibers (CFs) and multi-walled carbon nanotubes (MWCNTs) with varying weight percentages (AZ91D + 0.5% CF’s + 0.5% MWCNT and AZ91D + 0.75% CF’s + 0.75% MWCNT, respectively). The experimental tests were carried out to evaluate the mechanical and tribological behavior of the composites. The test results showed that the addition of CF and MWCNT reinforcements improved the hybrid Mg composite’s hardness, tensile strength, and impact strength compared to the base Mg matrix. The AZ91D + 0.75% CF’s + 0.75% MWCNT hybrid composite showed a 19%, 35%, and 66% increased hardness, tensile strength, and impact strength, respectively, compared to the base Mg AZ91D. The wear test results also showed the improved wear resistance of the Mg composite compared to the base matrix. The enhanced wear resistance of the composite is due to the addition of hard MWCNT and CF reinforcements. The wear rate of the AZ91D + 0.75%CF’s + 0.75% MWCNT composite for a load of 30 N at a sliding distance of 1500 m is lower as compared to the base matrix. The SEM micrographs of the worn surfaces revealed the existence of abrasive wear. The improved mechanical and tribological behavior of the magnesium composite is also due to the homogeneous distribution of the hard reinforcement particles along the grain boundaries.

Characterization and strengthening mechanism of CNT/TiB2 particulates added AZ91D composites

“…CNTs and TiB 2 microparticles may contribute to the dual-reinforced composite's mechanical strength [46]. As a result, load transfer, grain refinement of TiB 2 microparticles and CNTs, and hybrid reinforcement thermal mismatch all played a role in the impact of hybrid reinforcements on AZ91D matrix composites [47].…”

Tribological aspects of magnesium matrix composites: A review of recent experimental studies

“…This verifies the wear rate of the 20/0.5 sample is higher than that of other samples. It is well known that the uniform distribution of the reinforcement particles is required to improve tribological performance [127][128][129]. The authors reported that the agglomeration of CNT deteriorated the tribological performance.…”

Tribological Properties of Blocky Composites with Carbon Nanotubes

“…CNTs are effective as additives to improve the tribological properties of blocky composites [32]. Researchers are exploring their applications in chemical catalysis, energy conservation, and other fields [33]. However, while CNTs enhance the strength performance of blocky composite materials, there are also drawbacks such as poor dispersion and weak adhesion to the substrate surface which affect their level of enhancing wear-resistance properties of blocky composites.…”