Brazing of graphite to tungsten using graphene nanoplates reinforced TiNiCu composite filler

Graphene nanoplates (GNPs) reinforced TiNiCu composite filler (TiNiCuG) developed with which the brazing of graphite to W was achieved in this study. The effects of the GNPs reinforcement and brazing temperature (1120-1200°C) on the interfacial microstructure and mechanical properties of brazed joints were implemented in detail. Experimental results revealed that the bonding of graphite and filler material was achieved through the formation of a TiC reaction layer. A well bonded TiC/Ti(Ni,Cu) interface with lattice mismatch of 6.8% was observed by HRTEM. The FCC TiC and monoclinic Ti(Ni,Cu) taken the coherent orientation relations of [01̅1]fcc║[331]. The typical interfacial microstructure of graphite/W joint using TiNiCuG at 1180°C for 15 min was graphite/Ti(Ni,Cu)+ Ti2(Ni,Cu)+TiC /W(Ti)ss/W. The added GNPs reacted with Ti and in-situ synthesized TiC particles by reducing the residual stress to strengthen the brazed joint and increase the thickness of the brazing seam. The shear strength of the joint using composite filler reached the maximum value of 37.59 MPa, 132% higher than that joint without using GNPs.