Investigations on the surface effect of ultrasonic vibration-assisted 6063 aluminum alloy ring upsetting

The ultrasonic vibration-assisted 6063 aluminum alloy ring upsetting with different lubricants was performed to explore the effects of ultrasonic vibration on specimens during upsetting. The influence of ultrasonic vibration on upsetting was analyzed on the basis of the stress-strain curves which were obtained from different experimental conditions. The friction coefficients on the specimen/tool interface under different experimental conditions were computed according to the size of compressed specimens. The effect of ultrasonic vibration on surface quality was also investigated by analyzing the variation of surface hardness, roughness, and topography. Compared with the conventional upsetting, the true stress decreased by 14.26 and 15.45% when the amplitude was 3.34 and 3.96 μm respectively. The friction coefficient on the specimen/tool interface reduced under the effect of ultrasonic vibration, and the friction coefficient decreased with the increase of the vibration amplitude. The ultrasonic vibration improved the surface quality effectively. The surface quality, roughness, hardness, and anti-friction effect on the top surface that contacts directly with the vibration tool head were better than those on the bottom surface.