Microstructure, mechanical properties, and wear behavior of Al5083/GNPs nanocomposites prepared by powder metallurgy method

Abstract

This study focuses on the developing of Al5083 aluminum alloy matrix nanocomposites reinforced with graphene nanoplatelets (GNPs) to achieve a controlled microstructure, enhanced mechanical properties, and superior wear resistance. Nanocomposites with varying GNP concentrations (0.25, 0.5, 0.75, and 1 wt%) were fabricated using high-energy mechanical alloying (HEMA) followed by spark plasma sintering (SPS). The microstructure, morphology, chemical composition, and phase analysis were characterized using XRD, SEM, TEM/HRTEM, EDS, and Raman spectroscopy. Mechanical properties were evaluated through microhardness and compression tests, while wear resistance was assessed using the pin-on-disk method. The results indicate that HEMA and SPS processing leads to nearly complete alloying and uniform dispersion of GNPs. Adding of GNPs significantly improves the microhardness, compressive strength, and wear resistance of Al5083 due to strong Al/GNPs interfacial bonding and the absence of detrimental phases like Al₄C₃. The nanocomposite with 0.5 wt% GNPs exhibits the most uniform graphene distribution, resulting in optimal mechanical and wear performance. Compared to the unreinforced Al5083 alloy, this composite demonstrates a 36 % increase in microhardness, a 52 % improvement in compressive strength, and an 80 % reduction in wear rate. However, higher GNP concentrations results in the agglomeration, which negatively impacts the mechanical and tribological properties. The role of GNPs on the strengthening and wear mechanisms is discussed.