Experimental and numerical investigation of ultrasonic-assisted tensile behavior in face-centered cubic metals with different stacking fault energies

Ultrasonic vibration–assisted deformation is known to reduce flow stress in metals; however, the potential of this technique remains largely unexplored. In this study, a novel ultrasonic vibration system was developed and, for the first time, applied to high-strength alloys such as AA2014, alongside AA6063, Brass, and Copper. The governing factors of this softening mechanism were systematically evaluated using a full factorial experimental design. Three variables were examined: material type, representing different stacking fault energies, ultrasonic amplitude, and frequency. Tensile experiments were conducted at a constant frequency of 20 kHz. Statistical analysis revealed that ultrasonic treatment exerted the dominant effect on stress reduction. Specifically, the application significantly reduced forming forces compared to conventional methods. X-ray diffraction analysis indicated decreased dislocation density and modified stacking fault characteristics under acoustic excitation, suggesting enhanced dynamic recovery mechanisms. These findings establish a quantitative and microstructural basis for ultrasonic vibration-assisted forming processes.