Microstructure-based modeling of the PMZ mechanical properties in 2219-T8 aluminum alloy TIG welding joint

Partially melted zone (PMZ) is generally the weak region in 2219-T8 aluminum alloy TIG welding joint. In this work, a microstructure-based numerical simulation was performed to analyze the tensile behavior of PMZ. The constitutive behavior and damage mechanism of eutectic structure and Al matrix were determined. Stress–strain distribution and fracture behavior in tensile process were analyzed. Quantitative relationships between eutectic structure and tensile properties of PMZ were proposed. The results showed that the maximum area and clustering of eutectic particles have significant effects on the tensile strength and elongation. Plastic strain mainly concentrated in matrix, and stress concentration occurred in larger eutectic. The tensile cracks initiated from eutectic structure and then propagated into matrix and resulted in the final fracture.