Laser sintered graphene nickel nanocomposites

Laser sintered graphene nickel (Gr-Ni) nanocomposites have been successfully fabricated, with uniform dispersion of graphene nanoplatelets in the nickel matrix. Microstructures and composition of the nanocomposites were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and Raman spectroscopy. It was demonstrated by EDS maps, XRD patterns and Raman spectrum that graphene nanoplatelets were uniformly integrated in the nickel matrix. TEM images further proved the structure and uniform distribution of graphene in the nanocomposites after laser sintering. HRTEM images revealed the interface between nickel and graphene. High density of dislocation was discovered around the graphene. The strength and elastic modulus of the nanocomposites are significantly improved, as characterized by nanoindentation tests. The hardness tests show that the laser sintered Gr-Ni nanocomposites are around 3-fold higher than that of laser sintered nickel. The strengthening mechanism was also studied theoretically.