Effects of graphene nanoplatelets and boron carbide on microstructure and mechanical behaviour of aluminium alloy (Al6061) after friction stir welding

ABSTRACT

Friction stir welding (FSW) has gained enormous attention as a well-established solid-state welding technique. Loss of strength and compromise on heat-affected zone has always been an issue in welding. The addition of Graphene Nanoplatelets and Boron Carbide in Al6061 via FSW has been studied hereby. The effect of individual and hybrid combination of both reinforcements in the Al6061 matrix was explored by using a comparative approach with non-reinforced FSW reference. A detailed microstructural investigation, utilising the optical and scanning electron microscopy was conducted. The mechanical behaviour was examined by employing micro-hardness and tensile testing. Fractography was carried out to inspect the tensile tested fractured FSW samples. Maximum strength was displayed by the boron carbide added FSW joint at the cost of ductility. The tendency of graphene nanoplatelets to cluster led to the deterioration of mechanical profile at the respective FSW joint. A dominant behaviour of boron carbide was observed in the hybrid combination of the reinforcements at the FSW joint.

KEYWORDS:

• Friction stir welding (FSW)
• graphene nanoplatelets (GNPs)
• boron carbide (B₄C)
• aluminium matrix composite
• mechanical properties
• microstructure

Acknowledgments

The authors acknowledge the financial support of the Higher Education Commission of Pakistan (Grant No. 213-53249-2EG2-102) provided under the PhD indigenous fellowship; Phase-II Batch-II, as well as the Norwegian University of Science and Technology (NTNU), Norway, for the use of their laboratory facilities for processing and characterization.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Commission on Higher Education [213-53249-2EG2-102].