Nondestructive measurement of the mechanical properties of graphene nanoplatelets reinforced nickel aluminium bronze composites

Nanoindentation is a viable method to assess the mechanical properties of developed alloys and composites at the nanometer scale without hampering the microstructure and integrity of materials. In this study, nondestructive measurement was conducted on spark plasma sintered nickel aluminium bronze (NAB), and graphene nanoplatelets (1, 2, 3 wt.%) reinforced NAB composites using the nanoindentation technique. The nondestructive measurements were conducted under loads of 50 mN and 100 mN to assess the nanohardness and reduced elastic modulus of the fabricated NAB alloy and composites. Further investigations were carried to evaluate the elastic recovery index, plasticity index, the nanohardness and reduced modulus ratio, and the yield pressure to reveal the nanomechanical responses of the fabricated materials. Scanning electron microscopy was used to analyze and reveal the dispersibility of the graphene nanoplatelets (GNP) in the NAB matrix. The nondestructive measurements showed that the nanohardness, reduced elastic modulus, yield pressure, resistance to elastic strain to failure and the elastic recovery index improved with the presence and increase in the concentration of GNP in the NAB matrix. The reduced elastic modulus and nanohardness values range from 34.2 – 43.0 GPa and 4407.2–6598.8 MPa respectively, which declined with nanoindentation loads. The fabricated NAB alloy experienced the maximum plastic deformation and least resistance to impact loading.