Uniform dispersion and interface analysis of nickel coated graphene nanoflakes/ pure titanium matrix composites

An increasing number of reports have demonstrated enormous strength enhancements in titanium matrix composites (TiMCs) reinforced with graphene nanoflakes (GNFs) on account of the superior mechanical properties of GNFs. Unfortunately, the difficulty of uniform dispersion and severe interfacial reaction are simultaneously the most challenging and serious issues in GNFs reinforced TiMCs. In this work, we applied electroless plating method to prepare Ni decorated GNFs (Ni-GNFs) as a reinforcement in Ti matrix to uniformly disperse the GNFs in Ti matrix and relieve the severe interfacial reaction between metal and carbon nanophase. The composite reinforced by low content Ni-GNFs (0.05 wt%GNFs) exhibiting ultimate strength of 793 MPa (+40% compared to monolithic pure Ti), have been processed by short time ball milling process followed by spark plasma sintering (SPS) and hot-rolling (HR). Enormous strength increase of the composite can be attributed to a homogeneous distribution of Ni-GNFs in the Ti matrix coupled with the formation of special interface (Ti/Ti₂Ni/nano-TiC_X/Ni-GNFs). The load transfer mechanism of Ni-GNFs in composites was investigated by in-situ tensile test, which shows the great interfacial load transfer capability. This work provides a new strategy for dispersion and interface analysis of GNFs reinforced Ti matrix composites.