Experiment and Modelling of Ultrasonic Vibration-Assisted Creep-Aging Tensile for 7055-T6 Alloy

This study investigates the effects of ultrasonic vibration on the creep-aging tensile behavior of 7055-T6 aluminum alloy through experiments and finite element simulations. Two characteristic parameters—effective softening amplitude (ESA) and recovery amplitude (RA)—are introduced to quantify the competing softening and hardening effects induced by ultrasonic vibration. Experimental results reveal that the maximum ESA (28.1 MPa) occurs at an amplitude of 14.01 μm, whereas optimal plasticity is achieved at 12.53 μm, indicating that maximum softening does not coincide with optimal formability. Intermittent vibration enhances creep plastic strain by up to 6.95% at 12.53 μm, contrasting with the detrimental effect of continuous vibration. A viscoplastic constitutive model incorporating the volumetric effect of ultrasonic vibration is developed and validated via finite element simulations, achieving close agreement with experiments (ESA deviation ≤ 1.9 MPa). These findings provide quantitative guidance for parameter optimization in ultrasonic-assisted creep-aging formation.