Ultrasonic-assisted wire arc additive manufacturing significantly improves impact toughness of 5183 aluminum alloy

Wire arc additive manufacturing (WAAM) is a promising method for fabricating large-scale, lightweight aluminum alloy structures due to its high deposition rate, material efficiency, and design flexibility. However, as-deposited WAAM aluminum alloys often suffer from porosity and predominantly columnar grain structures, both of which compromise mechanical properties and hinder industrial adoption. In this study, an innovative ultrasonic-assisted WAAM (UA-WAAM) approach is proposed. A comparative analysis of porosity, microstructure, and mechanical properties between conventional WAAM and UA-WAAM samples is conducted to systematically investigate the effects of ultrasonic vibration. Microstructural analysis confirms significant grain refinement and reduced residual stress in UA-WAAM samples, attributed to ultrasonic cavitation disrupting epitaxial grain growth. Furthermore, the introduced ultrasonic vibration effectively suppresses porosity by enhancing molten pool dynamics and reducing crack initiation sites. Consequently, the UA-WAAM material exhibits a 76% higher impact toughness than conventional WAAM. Elongation increases by 49% in the vertical direction and 21% in the horizontal direction, while the ultimate tensile strength is improved by 12% in both orientations.