Interface-free novel joining of additively manufactured Al-Si 5wt.% alloy through diffusion bonding

•Novel way for joining WAAM components.•A special interface treatment at faying surfaces.•The estimated and measured diffusion length of Ga are in good agreement.•Direct diffusion bonding enabled the formation of IMC and void free joint. Wire-Arc Additive Manufacturing (WAAM) is popular because layer-by-layer metal deposition generates complex structures like compact heat exchangers without the need for an expensive setup. Diffusion bonding of Wire Arc additively manufactured (WAAM-DB) Al-Si5wt.% alloy is discussed. A special interface treatment is utilized to facilitate the successful joining in the air furnace.