Microstructural Evaluation of Inductively Sintered Aluminum Matrix Nanocomposites Reinforced with Silicon Carbide and/or Graphene Nanoplatelets for Tribological Applications

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 49; no. 7; pp. 2963 - 2976
• Main Authors: Islam, Mohammad, Khalid, Yasir, Ahmad, Iftikhar, Almajid, Abdulhakim A., Achour, Amine, Dunn, Theresa J., Akram, Aftab, Anwar, Saqib
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.07.2018; Springer Nature B.V
• Subjects: Abrasive wear; Aluminum; Casting; Characterization and Evaluation of Materials; Chemistry and Materials Science; Coefficient of friction; Consolidation; Debris; Densification; Diamond pyramid hardness; Dislocation pinning; Dispersion; Grain refinement; Graphene; Materials Science; Metallic Materials; Metallurgy; Nanocomposites; Nanotechnology; Silicon carbide; Sintering (powder metallurgy); Structural Materials; Surfaces and Interfaces; Synergistic effect; Thin Films; Tribology; Wear mechanisms; Wear particles; Wear rate; Wear resistance
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-018-4625-0

Silicon carbide (SiC) nanoparticles (NP) and/or graphene nanoplatelets (GNP) were incorporated into the aluminum matrix through colloidal dispersion and mixing of the powders, followed by consolidation using a high-frequency induction heat sintering process. All the nanocomposite samples exhibited high densification (> 96 pct) with a maximum increase in Vickers microhardness by 92 pct relative to that of pure aluminum. The tribological properties of the samples were determined at the normal frictional forces of 10 and 50 N. At relatively low load of 10 N, the adhesive wear was found to be the predominant wear mechanism, whereas in the case of a 50 N normal load, there was significant contribution from abrasive wear possibly by hard SiC NP. From wear tests, the values for the coefficient of friction (COF) and the normalized wear rate were determined. The improvement in hardness and wear resistance may be attributed to multiple factors, including high relative density, uniform SiC and GNP dispersion in the aluminum matrix, grain refinement through GNP pinning, as well as inhibition of dislocation movement by SiC NP. The nanocomposite sample containing 10 SiC and 0.5 GNP (by wt pct) yielded the maximum wear resistance at 10 N normal load. Microstructural characterization of the nanocomposite surfaces and wear debris was performed using scanning electron microscope (SEM) and transmission electron microscope (TEM). The synergistic effect of the GNP and SiC nanostructures accounts for superior wear resistance in the aluminum matrix nanocomposites.