Optimizing powder metallurgy methods: Effects of carbon nanotube dispersal mechanisms on mechanical properties of aluminium/carbon nanotube composites

Abstract

The influence of carbon nanotube dispersion techniques (surfactant-assisted dispersion, ultrasonication and magnetic stirring) and surface functionalization of carbon nanotubes on mechanical properties of nanocomposites fabricated via powder metallurgy techniques is characterized. Functionalized multiwalled carbon nanotubes dispersed using a combination of techniques results in Al/functionalized multiwalled carbon nanotube composites with excellent microstructure and enhanced mechanical properties. Nonfunctionalized carbon nanotubes dispersed using zwitterionic surfactants show good dispersion patterns on Al powder surfaces and results in composites with good strength and relative densities are also obtained. Carbon nanotubes dispersed solely via shear mixing techniques resulted in highly embrittled composites with poor microstructure. Also discussed in this study is the usefulness of scanning electron microscopy in conjunction with image analysis techniques in characterizing porosity in Al/carbon nanotube composites.

Investigation of magnetite concentrate utilization as reinforcement in aluminum matrix composites

“…Although process parameters like particle sizes of both reinforcement and matrix metal, compaction pressure, sintering time, and temperature affect the agglomeration of the particles 55 ; there are also varying methods suggested in the literature to lower the particle agglomeration regardless of the reinforcement type. 17 Rael et al 16 used ultrasonication to disperse the carbon nanotubes in Al powder and achieved an effective dispersion, and therefore, porosity was lowered where higher mechanical properties were obtained. During the liquid phase production of (Al–Si)/SiCp composites, Gui et al, 56 utilized both liquid and semi-liquid mechanical stirring processes to improve dispersion of the reinforcements and accordingly lowered the porosity of the final product.…”

“…The ceramic particulate-reinforcements like Al 2 O 3 , 13,14 graphite, 3,15 carbon nanotube (CNT), 16,17 carbides like SiC, TiC, B 4 C, etc. 18,19 are widely used to increase mechanical properties like hardness, wear-resistance, and compression strength 3,[13][14][15][18][19][20][21][22][23][24][25][26][27] .…”

Development and characterization of multiwalled carbon nanotube-reinforced microwave sintered hybrid aluminum metal matrix composites: An experimental investigation on mechanical and tribological performances

“…All the three powders (Al, SiC, and MWCNT) are mixed with the ultra-sonication process for 90 min with a 10-s pulse-on time and 2-s pulse-off time in isopropanol, as optimized by the authors. 25 After the ultra-sonication, evaporation of isopropanol was carried out. Further, the mixed powder was put in the heater to remove the moisture and isopropanol to form a dry powder.…”

Effective functionalisation of carbon nanotubes for reinforcement application in liquid state processed aluminium composites: A relatively greener approach

“…18 Presently many material scientists emphasise to use CNTs as reinforcements in aluminium matrix composites (AMCs), as the CNTs improve their hardness, strength, toughness, resistance to creep and wear remarkably. 5,[19][20][21][22] However, the dispersion pattern and matrix-reinforcement interface strength have challenged the viability of CNTs as potential reinforcements in AMCs. It is difficult to attain uniform dispersion of CNTs in matrix metal because of the strong Van der Waals forces between them and p-p stacking of individual tubes.…”