Research On The Formability Of AZ31 Magnesium Alloy Sheet Under Warm And Driving In Electromagnetic Forming

This paper based on AZ31 magnesium alloy sheet at the different temperatures under warm and driving in electromagnetic bulging forming experiment,the quasi-static forming limit forming experiment,AZ31 magnesium alloy sheet at the different temperatures under warm drive electromagnetic forming limit experiment,conduct the thorough research to the changes in microstructure and fracture morphology characteristics,revealing the AZ31 magnesium alloy sheet warm drive the formability of the electromagnetic pulse forming.The influence factors of the forming of AZ31 magnesium alloy sheet in the high rate of electromagnetic pulse were studied by electromagnetic pulse bulging test.Results show that when Electromagnetic forming,the driver sheet has the inertial effect and impact effect.That is helpful to improve the ability of magnesium alloy sheet bulging,and driven by 1.0 mm A1 sheet makes magnetic pulse bulging effect is better.In a certain range(at room temperature to 250 ?),ascending temperature is beneficial to improving the capacity of AZ31 magnesium alloy sheet electromagnetic pulse bulging,electromagnetic pulse temperature driven bulging tests best at 200 ?.The experimental data are analyzed and processed to lay a foundation for the test of the forming limit of the electromagnetic pulse temperature of AZ31 magnesium alloy sheet.Based on the combination of temperature and electromagnetic pulse drive forming forming way of forming,the width of the sample by changing the standard for AZ31 magnesium alloy sheet is aim at getting the different loading ways of the temperature of three kinds of strain(uniaxial tensile,plane strain,two-way stretch)under electromagnetic pulse warm forming limit.By comparing the quasi-static forming limit test,electromagnetic pulse drive warm forming manner to improve the AZ31 magnesium alloy forming performance impact,build complete electromagnetic pulse AZ31 magnesium alloy sheet warm forming limit diagram.The results show that the electromagnetic forming limit is much higher than the quasi-static forming limit.At room temperature,the forming limit of single-pull state was increased by 430%.In plane strain state,the increase was 358%;Double-pull state,up to 265%.This shows that the forming limit strain of AZ31 magnesium alloy plate is increasing greatly under the magnetic pulse,and the shaping performance is improved effectively.A certain range,the electromagnetic forming under high strain rate,with the temperature from room temperature,strain increases gradually,but the temperature 200 ? when the forming principal strain is much better than 250 ?,showed the ascending temperature under high strain rate to improve formability AZ31 magnesium alloy effect is not obvious.The microstructure and microstructure of AZ31 magnesium alloy sheet were revealed by means of optical microscope and scanning electron microscope.Research shows that:when the AZ31 magnesium alloy sheet under 25 ? with the increase of discharge voltage electromagnetic force,magnesium alloy plate obviously refined grains,with twin appear at the same time.Microstructure under driver slice thickness of 1.0 mm,obvious grain size,relative to other thickness drive,forming effect is best,drive the slice thickness of 1.0 mm,the temperature of 200 ? under the uniform and refined grains,show the best forming warm forming effect;Magnesium alloy sheet rupture mode mainly for brittle fracture under quasi static,as temperatures rise,fracture morphology is still present state of river pattern,but with the toughening nest,the AZ31 magnesium alloy sheet specimen fracture mode is ductile-brittle fracture,a certain range,when the forming temperature is advantageous to the shape forming ability increases.Although driven electromagnetic pulse AZ31 magnesium alloy sheet warm forming limit microscopic fracture morphology of toughening fossa relative to the quasi-static forming limit microscopic fracture morphology of toughening nest was less and less,no apparent necking phenomenon.But the AZ31 magnesium alloy sheet warm drive the formability of the electromagnetic pulse boosted by electromagnetic forming,uniform deformation due to the high strain rate,temperature,this is the key to improve the performance of plastic forming on the AZ31 magnesium alloy sheet.