A new insight into porosity suppression in additive manufacturing of TiC nanoparticle-enabled aluminum alloys

Hydrogen-induced porosity remains a critical issue in additive manufacturing of aluminum alloys, undermining structural reliability and performance. Material modification strategies for porosity suppression remain underexplored and require further investigation. This study demonstrates a nanoparticle-enabled material design strategy for intrinsic porosity suppression. Incorporation of TiC nanoparticles reduced porosity by 96.8 % and refined grain size from 108 μm to 12 μm, producing a fully equiaxed and isotropic microstructure. Multiscale analysis and first-principles calculations revealed that site-selective hydrogen adsorption on TiC surfaces serves as the primary suppression mechanism. Two synergistic effects further contribute: (i) interfacial dispersion promotes high-angle boundary formation, increasing hydrogen trap density; and (ii) thermal modulation extends the mushy zone, enhancing hydrogen redistribution and bubble escape. These effects enable in-situ mitigation and spatial homogenization of porosity. This material-driven approach offers a promising path for in-situ porosity mitigation and design of defect-tolerant alloys in additive manufacturing.