Effect of the Ti-6Al-4V powder size on the microstructure and mechanical properties of composites with nickel-coated graphene nanoflakes

Abstract

In this study, 0.5 wt% Ni-P@GNF/ Ti-6Al-4V composites with different particle sizes (0–25, 15–53 and 53–150 μm) were fabricated via chemical nickel plating and speak plasma sintering. The plasma sintering temperature and the sintering pressure were 900 °C and 50 MPa, respectively. The microstructure and mechanical properties of the three composites were investigated via optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and compression experiments. The results showed that the microstructures of the composites were refined, and the compressive strength of the Ti-6Al-4V incorporated with graphene nanosheets was higher than that of the pure Ti-6Al-4V. Herein, with 0–25 μm Ti-6Al-4V powder, the compressive strength of 0.5 wt% Ni-P@GNFs/TC4 composite reaches 1339 MPa, which was an increase of 37.91% versus Ti-6Al-4V alloy (970 MPa). Moreover, with increasing spherical powder particle size, the size of the reinforcing phase of the network structure was coarser, and the plasticity was improved. • Ni addition could decrease the interfacial reaction of composites. • The particle size was beneficial for grain refinement of composites. • The homogeneous dispersion of GNFs lead to load strengthening and network structure