Wire arc additive manufacturing of network microstructure (TiB+TiC)/Ti6Al4V composites using flux-cored wires

Titanium matrix composites (TMCs) with ceramic particles exhibit higher hardness, strength, and wear resistance than those of titanium alloys. Wire arc additive manufacturing (WAAM) is a promising method for fabricating large TMC components owing to its high deposition rate and low production cost. In this study, a WAAM process using a flux-cored wire was developed to fabricate components of TiB plus TiC reinforced Ti6Al4V matrix composites. The network microstructure of the reinforcement was obtained through in-situ reactions induced by the B₄C and C powders in the flux core. The formation mechanism of the network microstructure was discussed. The effect of the reinforcement fraction (5 and 10 wt%, hereinafter called 5 and 10 wt% samples) on the microstructure and wear resistance of the samples along the deposition direction were investigated. The results showed that the refined net-basket-dominated (α＋β)-Ti matrix and stable network microstructure were formed in middle region owing to the introduction of the reinforcement. The microhardness increased by 23% and 35% when the reinforcement fractions were 5 and 10 wt%, respectively. The 10 wt% sample showed reduced wear performance because more cracks appeared as the result of the decreased ductility.