On shear-lag and thermal mismatch model in multiwalled carbon nanotube/copper matrix nanocomposites

► Successful fabrication of MWCNT/Cu nanocomposites by hot forging technique. ► Enhanced elastic modulus and hardness of the nanocomposites. ► Comparison of elastic modulus and hardness with the theoretical models. Nickel-coated and uncoated multiwalled carbon nanotube/copper (MWCNT/Cu) nanocomposites with different MWCNT weight fractions were fabricated by powder metallurgy processes and subsequent hot forging. Microstructural characterization by transmission electron microscopy revealed a uniform dispersion of MWCNTs both inside the grains and at the grain boundaries. Increased elastic modulus and hardness, due to incorporation of uncoated and nickel-coated MWCNTs was observed by nanoindentation. The elastic modulus and hardness of the 3wt.% nickel-coated MWCNT/Cu nanocomposite were increased by 7% and 14% respectively compared to 3wt.% uncoated MWCNT/Cu nanocomposite. These results provides evidence for the importance of the nickel coating in achieving a good interfacial bond between the MWCNTs and the copper matrix for efficient load transfer during deformation and for the development of high strength composites. The mechanical properties of nanocomposites were theoretically estimated using shear-lag and thermal mismatch model.