Microstructure and mechanical behaviour of TiCx-MLG-TiCx network reinforced Ti6Al4V fabricated with core-shell structure powders

Abstract

In this work, the sandwiched TiCx-MLG-TiCx network reinforced Ti6Al4V composite (MLG@Ti6Al4V) was prepared with core-shell structure powders, in which Ti6Al4V core was anchored by multi-layer graphene (MLG) shell exfoliated from graphite balls via 3D vibration milling. After consolidation by spark plasma sintering (SPS), the robust interface is generated between MLG and Ti6Al4V matrix taking advantage of the in-situ synthesized TiCx (Ti8C5 + TiC), which favors an effective load transfer. The interlinked TiCx and MLG construct TiCx-MLG-TiCx network reinforcements that wrap around the matrix, endowing the composite with near equiaxed α phase and fine grains. The improved interface bonding, dislocation blocking and grain refinement provided by the TiCx-MLG-TiCx network result in an increased magnitude of 14.5% and 19.9% in the yield strength and ultimate strength, respectively, compared with monolithic Ti6Al4V. Also, the TiCx-MLG-TiCx network conduces to a well-maintained ductility of 10.7% for the composite associated with the deformation compatibility, the near equiaxed α phase as well as the fine grains.