Investigation of Microstructure Evolution and Mechanical Properties in AA7075 Butt Joint with 0.7 TiC Nanoparticles Reinforced Wire

Nowadays, how to achieve high strength welding of 7xxx aluminum alloy has attracted much attention. In this article, the melt inert gas (MIG) welding test of aluminum alloy 7075 (AA7075) is carried out by using the self‐developed welding wire of Al‐Zn‐Mg‐Cu‐0.7 TiC nanoparticles (NPs). The microstructure and mechanical properties of nanoparticle‐enhanced AA7075 are investigated in detail. The results show that the α‐Al grain size in the weld seam remained stable after heat treatment due to the pinning effect of TiC NPs on the grain boundaries. After T6 heat treatment, the strength coefficient, the average hardness, the tensile strength, and the elongation increased by 100.2%, 22.1%, 100%, and 76%, which is mainly due to the strengthening effect of TiC NPs and η‐MgZn₂. This work proves that AA7075 has the potential to form high‐strength welded joint by MIG welding.