Mechanical and tribological properties of Self-Lubricating Al 6061 hybrid nano metal matrix composites reinforced by nSiC and MWCNTs

Abstract

Numerous investigations have been carried out using carbon nanotubes (CNTs) as reinforcement in different matrix materials. Uniform dispersion of CNTs throughout the matrix material has been the main challenge. This is due to the higher surface area of the Nano particulates, which led to form clusters because of van der Waals forces. Hence, a homogeneous distribution of CNTs is essential as it translates into homogeneous properties throughout the metal matrix composite materials. Al 6061 matrix composite materials reinforced with CNTs and nSiC were fabricated by mechanical ball milling and sintering. nSiC Nano particulate was used as a secondary dispersion agent to distribute CNTs uniformly throughout the Al 6061 matrix. The ball milled composite powders and bulk composites were studied using optical microscopy, FESEM, elemental mapping, XRD, Raman Spectroscopy analysis, and microhardness. The wear characteristics of these hybrid Nanocomposites were evaluated using Pin-On-Disc. Effect of nSiC addition to the existing Al 6061 + MWCNTs has been investigated. The microhardness of the fabricated hybrid composites is 3 times higher than the single reinforcement of MWCNTs in Al 6061 matrix. The formation of new phases like Al4C3 and CrC play a major role in enhancing the hardness of the composites. The surface roughness of the hybrid composites is directly proportional to its hardness. The uniform distribution of hardness in hybrid nanocomposites results in reduction of wear rate.