Individual and collective effects of titanium carbides and multi-walled carbon nanotubes on reinforcing the Inconel 625 alloy fabricated by laser powder bed fusion

Nano-additives reinforced Inconel 625 alloys were manufactured by laser powder bed fusion (LPBF), consisting of titanium carbide nanoparticles (TiC) and/or nickel-coated multi-walled carbon nanotubes ((Ni)MWCNT). Microstructural characterization revealed that respective structures of TiC and (Ni)MWCNT nano-additives were retained, while the (Ni)MWCNT experienced fragmentation into shorter segments after ball milling and LPBF. Compared to LPBF In625, the reinforced samples showed enhanced ultimate tensile strength, yield strength, and hardness, despite decreased elongation to failure. Nano-additives exert varying effects on the properties of the alloys. Individually, (Ni)MWCNT strengthens the alloy, and TiC plays an insignificant role; collectively, they strengthen the material to a higher degree, via refining the cell size and probably increasing dislocation density.