Comparative study of mechanical performance between Al–Graphite and Cu–Graphite self-lubricating composites reinforced by nano-Ag particles

Abstract

Copper and aluminum metals are classified relatively as softer materials that possess comparatively poor mechanical and wear characteristics; accordingly, this study has aimed an attempt to improve their properties and compare between them. At the present work, both copper and aluminum metals were used separately as a matrix composite for a comparative study. They reinforced with a fixed content of 4 vol% graphite as a solid lubricant and various content of 0, 1, 2, 3, and 4 vol% silver nanoparticles. The pure metals and the hybrid nanocomposites were manufactured by utilizing the powder metallurgy technique. Mechanical properties such as hardness, diametral compressive strength, and tensile strength were studied. Moreover, a dry wear test was performed by applying various loads of 5, 10, 15, and 20 N with constant sliding distance and speed of 1810 m and 1.5 m/s, respectively. In order to interpret the results and prove the preparation goodness, Field Emission Scanning Electron Microscope (FESEM) and Energy-Dispersive X-ray (EDX) analysis were employed to characterize the as-received composite powders, worn surface, and wear debris morphology. The results were revealed that the microhardness, diametral compressive strength, tensile strength, friction coefficient, and wear resistance were improved significantly by increasing silver nanoparticle content up to 2 vol% and 3 vol% in aluminum and copper matrix composites, respectively, and then deteriorated gradually as compared with pure metals. Convergence was observed in the wear rate results between the copper and aluminum matrix composites in the silver content of 2 vol%. Besides that, the increment in applied loads was associated negatively with the wear resistance. Lastly, the impact of improving silver nanoparticles content on strengthening the copper matrix composite is higher than aluminum matrix composite.