Role of Powder Metallurgical Processing on Mechanical Response of Nickel–Phosphorus-Coated Graphene Nanoflakes/Titanium Matrix Composites

Herein, the nickel–phosphorus-coated graphene nanoflakes/Ti6Al4V composites (Ni-P@GNFs/Ti6Al4V composites) are fabricated by spark plasma sintering (SPS) and hot isostatic pressing (HIP), respectively. The results show that the Ni-P@GNFs/Ti6Al4V composites prepared by SPS, in which the agglomeration of Ni-P@GNFs is weak and the size of α phase is small, possess improved mechanical properties relative to those of the Ni-P@GNFs/Ti6Al4V composites prepared by HIP. The compressive yield strengths of Ni-P@GNFs/Ti6Al4V composites prepared by SPS enhance from 1116.29 MPa (0 wt% GNFs) to 1367.33 MPa (1 wt% GNFs), and microhardness increases from 302.83 to 479.43 HV. The Ni-P@GNFs/Ti6Al4V composites prepared by HIP reach a yield strength of 1299.59 MPa and microhardness of 410.10 HV. In addition, serious agglomeration of GNFs leads to a significant drop in ductility (from 47.47% to 25.76%) in the Ni-P@GNFs/Ti6Al4V composites prepared by HIP.