Thermal and Mechanical Properties of Graphene-Titanium Composites Synthesized by Microwave Sintering

The x wt% graphene-Ti composites (x = 0, 0.2, 0.3 and 0.4) were obtained using the powder metallurgy method. The X-ray diffraction results demonstrated that the peak intensity of graphene increased monotonically with increasing graphene content. Furthermore, the number of grain boundary and interface between graphene and matrix increased as graphene increased, which led to a sharp rise of thermal resistances. The thermal conductivity and specific heat capacity of composites initially decreased drastically with addition of graphene, but then increased with increasing graphene content from 0.2 to 0.4 wt%. This phenomenon was connected with the graphene content and the characteristics of Ti matrix (pores, grain boundary and interface between graphene and matrix). The variation of the compressive strength of composites was attributed to the interaction effects of the average grain size of the Ti matrix (d(m)) and the volume fraction (V-f) and aspect ratio (lambda) of graphene.