Al–CNT–Ni composite with significantly increased strength and hardness

Abstract

In this study, aluminium-carbon nanotube-nickel (Al-CNT-Ni) composite was prepared by powder metallurgy from pure Al powder and Ni-encapsulated CNT. Previously, carbon nanotubes were coated with nickel following ultraviolet-assisted electroless deposition method. Tensile strength and hardness of the composites were found to increase in proportion to the CNTs addition. For an addition of 7 wt.% Ni-coated CNTs containing 2.5 wt.% nanotubes of 8-15 nm diameter (Ni to CNT ratio was 1-0.357), resultant tensile and yield strength were increased by 129.26% and 157.48% respectively compared to pure aluminium. Hardness was also increased by 171.39%. These results were obtained while conventional sintering was followed by further consolidation by Hot Isostatic Pressing (HIP). Enhanced mechanical properties are attributed to the well dispersion of CNTs in aluminium matrix and strong interfacial bonding between CNT and aluminium. Well dispersion of CNTs and strong interfacial bonding was resulted from the uniform Ni-encapsulation as verified by red shift in Raman Spectroscopy.

Enhanced mechanical properties of carbon nanotube-reinforced magnesium composites with zirconia fabricated by spark plasma sintering

“…However, weight reduction of structural materials by light metals often leads to decrease in strength, which causes problems in terms of safety and sustainability. 1,2 The application of magnesium and its alloys has been widespread in aerospace and automobile industries because of their low density, high specific strength and specific stiffness. However, their relatively low absolute strength and stiffness limit their further development, which can be overcome by strengthening using reinforcements, including ceramic and metallic fibers, particles, and carbon fibers.…”

“…Namely, difficulty in the processing is represented by the uniform dispersion of CNT in Mg matrix without any damage of the nanotubes. [22][23][24][25][26] In addition, it has been reported that there are two main challenging issues attributed to the fabrication of Mg matrix composites, which consists of: (1) Extensive oxidation and explosive behavior of Mg. (2) The high reaction tendency with other components during fabrication processes. Lots of researches have been conducted to overcome these challenges by focusing on providing a protective surface to prevent oxidation behavior and processes including reaction elimination.…”

“…However, weight reduction of structural materials by light metals often leads to decrease in strength, which causes problems in terms of safety and sustainability. 1,2…”

Enhanced Mechanical Properties of Carbon Nanotube/Aluminum Composites Fabricated by Powder Metallurgical and Repeated Hot-Rolling Techniques

“…Recently, in order to cope with environmental issues such as CO 2 emissions reduction, replacing various structural materials like heavy metals such as iron (Fe) materials, comprising the major parts in automobiles, buildings, bridges, etc., with light metals such as aluminum (Al), magnesium (Mg), and titanium (Ti) has been highly desirable. However, the weight reduction of structural materials by light metals often leads to a decrease in strength, which causes problems related to safety and sustainability [1,2].…”

“…Depending on the number of carbon layers, CNTs can be classified into two categories: single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). Due to these interesting properties, CNTs can play a significant role in the fields of nanotechnology, electronics, optics, and materials science [2][3][4]. CNTs have been regarded as a powerful candidate for the reinforcement of metal matrix composites (MMCs) [5,6].…”