Improvement of microstructure and mechanical properties of CMT wire arc additive manufacturing Al-Si alloy deposition via interlayer coating TiC nanoparticles

Although cold metal transfer (CMT) wire arc additive manufacturing (WAAM) technology is commonly used in depositing aluminum alloy components, it encounters challenges and areas for improvement, particularly in Al-Si alloys. This study applies layer-by-layer TiC nanoparticle coating in the CMT-WAAM of ER4043 Al-Si alloy, investigating the impact of TiC nanoparticles on forming quality, electrical arc behavior, grain size, and mechanical properties. Results indicate that TiC nanoparticles enhance forming quality by influencing electrical arc behavior and altering the molten pool's surface tension. Owing to the minor lattice mismatch between TiC nanoparticles and the Al matrix, these nanoparticles serve as non-uniform nucleation sites, encouraging the formation of fine grains. The grain size in CMT-WAAM specimens coated with TiC nanoparticles layer-by-layer decreased from 118.24 mu m to 96.13 mu m, a refinement of 18.67 %. Specimen hardness increased from 52.58 HV to 64.79 HV, and tensile strength improved by 17.65 %. Additionally, the specimens' elongation at break was significantly enhanced.