Influence Of Electro-plastic Effect On AZ31Magnesium Alloy’s Flow Stress

Material flow stress model is the most basic function relationshipbetween flow stress and other parameters, and it is also the foundation ofdesigning and controlling the metal plastic deformation process. In thefield of plastic processing, the fundamental purpose of research on thematerial flow stress model is to describe flow stress change withtemperature, equivalent strain and strain rate, to improve calculation andsimulation accuracy of process design, to provide the reference basis of thesolution of plastic forming process and the choice of equipment.Under electric stimulation (including electron beam irradiation, pulseelectric current and electric field), the flow stress of materials decreasesand the plasticity increases, called electro-plastic effect.Magnesium alloy is brittle at room temperature and is difficult toprocess under plastic processing; Electrical plastic effect can assist in theplastic deformation of magnesium alloys, reduce the deformationresistance and improve the ductility. For the reason that making full use ofadvantage of electro-plastic effect to improve the forming performance, soit’s indispensable to study the Flow stress model of electro-plastic formingof the magnesium alloy to guide metal’s transformation.Based on Electro-plastic tensile experiment, get the stress-strain curveof magnesium alloy by the control variable method and find the influencesof charging voltage, charging frequency, temperature and strain rate onmaterial flow stress during forming process companied with electro-plasticeffect have been determined quantitatively. Modified constitutiveequations of Fields-Backofen, proposed the relation of flow stress of AZ31magnesium alloy. The charging voltage, charging frequency, temperatureand strain rate improvement determined the relation of flow stress change.To study the process behavior of roll hemming, and to validate the feasibility of electric pulse assisted roll hemming, the article has carried onthe test of the electric pulse assisted roll hemming.