Research Of Surface Effect Of Ultrasonic Vibration Assisted 6063 Aluminium Alloy Upsetting

Compared to traditional metal plastic forming process,ultrasonic vibration assisted plastic forming technology can lead to a reduction in forming force,metal flowing stress and the friction between die and specimens,improvement in the formability,surface quality and dimension precision of specimens.Due to these advantages,ultrasonic vibration assisted plastic forming technology has attracted more and more attentions of researchers both at home and abroad and can provide a new way to improve the property of plastic forming.This paper focused on the experiment and numerical simulation of ultrasonic vibration assisted upsetting forming process of 6063 aluminum alloy,and mainly studied the friction coefficient on the specimen/die interface,the influence of ultrasonic vibration on plastic forming process under different lubrication and vibration conditions and numerical simulation of ultrasonic vibration assisted upsetting forming process.The effect and mechanism of the ultrasonic vibration on 6063 aluminum alloy upsetting forming process were analyzed.The main researches are as follow:Based on the ring upsetting and energy method,the radius of the neutral layer was derived,the relationships between the reduction in height and the internal diameter of ring under different friction factors were established,and theoretical calibration curves of the friction coefficient during ring upsetting were obtained.The ultrasonic vibration assisted upsetting experiments of 6063 aluminum alloy were conducted under different lubrication conditions,and the friction coefficients on specimens/die interface were gotten under different lubrication and ultrasonic vibration conditions.The influence of the ultrasonic vibration on the interface friction was studied.Under different lubrication conditions,the 6063 aluminum alloy upsetting with and without the ultrasonic vibration was performed.The effect of the ultrasonic vibration on the forming load,flow stress,surface hardness,microstructure,surface morphology and surface roughness of upsetting specimens were investigated,and then the effects of surface effect induced by the ultrasonic vibration were revealed.The numerical modeling was established based on ABAQUS finite element software and the numerical simulation of ultrasonic vibration assisted upsetting was realized.The impacts of the ultrasonic vibration on deformation velocity,contact pressure,contact area,surface friction on specimen/die interface under different friction and ultrasonic vibration conditions were studied.The influence and action mechanism of the ultrasonic vibration on upsetting process were obtained.