Abstract
In the present study, AA-6061 and LF-06 aluminum alloys were subjected to pulsed Tungsten Inert Gas (P-TIG) welding using ER4043 (Al-Si) Filler alloy. A detailed microstructural examination revealed significant variations in the grain morphology, accompanied by the formation of intermetallic phases, notably Mg2Si, Al3Mg2, and Al3Fe, as well as the presence of both columnar and equiaxed grains. X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) analyses corroborated the identification of peaks corresponding to second-phase precipitates Mg2Si, Al3Mg2, and Al3Fe within the fusion zone (FZ). Notably, the welded joint exhibited no signs of porosity or hot cracking. Microhardness and nanohardness assessments demonstrated a significant increase in hardness, approximately 68% and 51% higher in the FZ compared to the AA-6061 base alloy, respectively. Furthermore, tensile test results indicated that the weldment strength of 132 MPa corresponds to ∼95% of the AA-6061 base alloy strength (139 MPa). AFM analysis demonstrated moderate pile-up behavior in the FZ compared to the base alloys, indicating localized plastic accommodation associated with microstructural heterogeneity and second-phase particles, without adversely affecting joint integrity.
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