Advance analysis of aluminum alloy welded joints microstructure

Abstract This study introduces a novel, quantitative approach to evaluate weld quality in AA2024-T3 aluminum alloys by analyzing three image-based microstructure parameters: average single-phase area (AASP), phase ratio (PR%), and number of single-phase zones (NSPZ). Using scanning electron microscopy (SEM) image processing and X-ray diffraction (XRD) phase mapping, we correlate these parameters with mechanical properties in tungsten inert gas and friction-stir-processed (TIG + FSP) joints with ER4047 filler. Key findings reveal that TIG + FSP joints achieve 38% higher tensile strength (310 MPa vs. 225 MPa for TIG), attributed to: • Fine-grained homogeneity (AASP reduced by 52–55%), • Optimal phase balance (PR% ≈ 50–60%), and. • Enhanced phase dispersion (NSPZ increased by 88–143%). XRD analysis confirms that FSP redistributes strengthening phases (Al₂Cu, Al₂CuMg) and mitigates Si segregation, explaining the mechanical improvements. Unlike subjective expert-based methods, our approach provides a repeatable, objective framework for weld quality assessment, with direct applications in aerospace and automotive industries.