Improvement in tensile properties of 2219-T8 aluminum alloy TIG welding joint by PMZ local properties and stress distribution

Tensile properties of 2219-T8 aluminum alloy TIG welding joints were seriously restricted by partially melted zone (PMZ) properties and stress concentration at weld toe. In this work, PMZ local properties were enhanced by refining grains size and θ phase particles in base metal. And the stress concentration at weld toe was adjusted using three-pass welding with swing. The results showed that tensile strength of PMZ was increased by ∼16–21 MPa, due to the higher Cu content of matrix, as well as reduced coarse and continuous eutectic. The joint tensile strength of ∼318 MPa (∼10% increase) and elongation of ∼5.8% (∼26% increase) were obtained by improving PMZ local properties and matching proper stress distribution.