The effect of ultrasonic vibration on stress-strain relations during compression tests of aluminum alloys

Complete understanding of ultrasonic interaction with aluminum alloys is essential to promote application of ultrasonic-assisted friction stir welding process in manufacturing industry. In this study, the ultrasonic-assisted compression tests were performed to investigate the effect of ultrasonic vibration on the stress-strain characteristics of AA2024-T3 alloy. At the same time, AA6061-T6 alloy was also tested, and the stress-strain relations for both alloys were compared and analyzed to study the influence of material properties on the variation of stress-strain characteristics under ultrasonic assisted compression. It was found that on the stress-strain curves of AA2024-T3 there are an obvious and transient stress reduction concave point at the beginning of ultrasonic exertion, a hysteresis of stress recovery and a short-term small hardening phenomenon after the ultrasonic exertion stopped. The results laid foundation for process optimization of ultrasonic-assisted friction stir welding of AA2024-T3.