Fabrication and Annealing of TiB Ti 6Al 4V Composites Using Laser Powder Bed Fusion Additive Manufacturing

Abstract

In this work, in-situ TMCs have been fabricated by incremental addition of elemental B and sub-micron TiB2 to Ti-6Al-4V powder. The effect of the addition of elemental boron in Ti- 6Al-4V alloy powder for in-situ fabrication of TiB/Ti-6Al-4V nanocomposites using laser powder bed fusion (L-PBF) additive manufacturing (AM) technique with commercial processing parameter of EOSINT 280 machine was studied. The microstructural evolution with varying boron addition was examined. The added boron (0.1-1.5 wt.%) reacted completely with Ti to form needle-like nano/micro TiB particles and induced grain refinement in the microstructure. The L-PBF fabricated TiB/Ti-6Al-4V composites with 0.5 wt.% B and above altered the microstructure drastically from martensitic lath to equiaxed and#945;. The microhardness and wear properties of the nanocomposite improved significantly with the increased concentration of boron. Nearly four-fold improvement in wear performance was associated with grain refinement and the formation of nano-sized TiB precipitates.