Abstract: Hydrogen-driven porosity is a major barrier to high-strength Al-Cu parts produced by wire-arc additive manufacturing (WAAM). We introduced 1.5 wt.% nano-TiC particles into Al-6.3Cu filler wire and calculated, from first principles, a hydrogen-trapping energy of 1.55 eV per H atom—three times that at θ′/Al interfaces. WAAM walls printed with this wire exhibited an average porosity of 0.015% versus 3.05% in the TiC-free reference, and an equiaxed grain size refined from 41 to 12 μm. After identical T6 treatment, the TiC-bearing alloy delivered yield and ultimate tensile strengths of 328 and 433 MPa, increases of 56% and 24%, respectively, while anisotropy improved to 0.96. Moreover, 90% of these strengths were retained after 100 h at 200 °C. These results provide the first quantitative evidence that TiC nanoparticles concurrently suppress processing and heat-treatment pores in WAAM Al-Cu and offer an immediately applicable pore-control route for high-performance Al additive manufacturing.

Key words: Wire-arc additive manufacturing, Al alloy, Porosity, Hydrogen, Mechanical properties