Interface-reaction reduction and hot rolling deformation of network structured graphene-TiB whiskers/Ti6Al4V composites by spark plasma sintering

For the sake of reducing the interface reaction between graphene (GR) reinforcement and Ti6Al4V (TC4) alloys matrix, the nano-TiB₂ particles were incorporated into GR/Ti interface after 3D dynamic mixing process, and TiB whiskers (TiBw) were formed by the subsequent reaction between TiB₂ and Ti after spark plasma sintering (SPS) process. The network structured GR-TiBw/TC4 composites were fabricated by 3D dynamic mixing and SPS with a subsequent hot rolling deformation. Effects of GR-TiBw hybrid reinforcement and hot rolling on the microstructure and mechanical properties of the composites were investigated. The results showed that the in situ formed TiBw reduced GR/Ti interface reaction and the content of GR-TiBw hybrid reinforcements had a great influence on the interface structure and mechanical properties of the composites. The suitable GR content combined with low content of nano-TiBw can form a quasi-continuous network interface structure and achieve a good trade-off between strength and ductility with a higher tensile strength and acceptable ductility. After obtaining a high rolling reduction, the quasi-continuous network interface structure was reconstructed and brought a noticeable increase of tensile strength with a slight loss of ductility.