<p>The increasing demand for lightweight, high-strength alloys in aerospace and automotive industries has made AA7075 a preferred choice for critical structural components. However, conventional fusion welding of this alloy is challenging due to solidification defects and loss of mechanical integrity. This study investigates the effect of traverse speed on the thermal, structural, and mechanical responses of AA7075 joints fabricated by friction stir welding. A combined experimental and finite element modeling approach was employed, with simulations conducted in ANSYS 2022 R1 and validated against embedded thermocouple data, showing only ~ 3% deviation. Results reveal that increasing traverse speed decreases heat input, leading to narrower heat-affected zones and refined grain structures in the stir zone. Energy dispersive spectroscopy and X-ray diffraction analyses confirmed the presence of intermetallic compounds such as MgZn₂, CuAl₂, and Al₇Cu₂Fe. Mechanical testing showed a maximum ultimate tensile strength of 390 MPa at 30&#xa0;mm/min, corresponding to ~ 64% of the base metal, with fracture surfaces indicating a ductile-to-brittle transition at higher traverse speeds. Fatigue crack growth rate analysis further highlighted superior cyclic resistance at lower traverse speeds. These findings demonstrate that traverse speed is a critical parameter for controlling weld quality and performance, and the integrated experimental–simulation approach provides valuable insight for appropriate friction stir welding of AA7075 in industrial applications such as aerospace fuselage assembly and lightweight automotive structures.</p> Graphical abstract <p></p>