Al 5251-based hybrid nanocomposite by FSP reinforced with graphene nanoplates and boron nitride nanoparticles: Microstructure, wear, and mechanical characterization

Essam B Moustafa,Asmaa M Khalil,A Melaibari,Ahmed O Mosleh,Ghazi Alsoruji

doi:10.1515/ntrev-2021-0108

Essam B Moustafa, Asmaa M Khalil + Show 3 more

Open Access

https://doi.org/10.1515/ntrev-2021-0108

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Abstract

Abstract The strength and wear resistance of aluminium alloys must be improved to enhance their usage in lightweight constructions. Thus, in this study, graphene nanoplates (GNPs) and boron nitride (BN) nanoparticles were reinforced into the Al 5251 aluminium alloy by friction stir processing (FSP). The Al 5251 aluminum alloy sheets were patterned with holes and filled by mono GNPs, mono BN nanoparticles and a hybrid of BN nanoparticles and GNPs. The microstructure, wear, and mechanical properties of the as-received, after FSP, and the manufactured surface nanocomposites were analysed. Wear tests were performed using two methods: weight loss and volume loss methods. FSP led to four times grain refinement. Due to the Zener pinning effect, the reinforcement nanoparticles improved the grain refinement effect by seven times decrease in the mean grain size. The wear rate by volume and weight loss with reinforcing BN nanoparticles decreased by 160 and 1,340%, respectively. Note that the GNP reinforcement insignificantly improved the wear resistance and hardness compared with the BN nanoparticles. The hardness was increased by 50, 120, and 80% by reinforcing the Al 5251 alloy with GNPs, BN, and a hybrid of BN nanoparticles and GNPs, respectively. The nanocomposite reinforced with GNPs exhibited superior mechanical properties compared to the other nanocomposites.

Highlights

Graphene is a two-dimensional single-layer crystalline material composed of carbon atoms
Surface nanocomposite reinforced with graphene nanoplates (GNPs) and boron nitride (BN) nanoparticles 1753 electrical, and thermal properties have recently attracted considerable research attention [1,2,3,4]
Because of its large aspect area ratio, superior thermal and mechanical properties, and lightweight, graphene is incorporated as a practicable reinforcement material for aluminium metal–matrix composites (AMMCs) [5,6,7]

Summary

Introduction

Surface nanocomposite reinforced with GNPs and BN nanoparticles 1753 electrical, and thermal properties have recently attracted considerable research attention [1,2,3,4]. Due to its good thermal, mechanical, and physical properties, in addition to its excellent lubricating property, boron nitride (BN) nanoparticles are most commonly used for strengthening AMMCs [11,12] Despite their high specific strength and superior thermal and electrical conductivities, aluminium-based alloys have limited application due to their low hardness and poor wear resistance. Their tribological properties can be significantly enhanced by reinforcing them with ceramic nano/microparticles. We compared the fabricated composites and as-received samples subjected to FSP based on microstructural analysis, tribological behaviour, and mechanical properties to identify the most influential reinforcement that significantly impacts the wear behaviour besides the refinement and mechanical properties. This research aims to study how incorporating two different reinforcement nanoparticles belonging to the same family impacts the fabricated metal–matrix nanocomposite

Experimental work

Microstructural analysis

Mechanical properties

Microhardness

Wear behaviour

Conclusion