Experimental Research On Forming Limit Of High Strength 7075-T6 Aluminum Alloy Under Warm Forming

With the automobile industry becoming the leading industry of our country's industrial development,a great deal of oil and gas consumption and environmental pollution come along.How to reform the development of automobile industry,and to reduce the dependence on the environment has become the main development direction of the major automobile manufacturers,high strength and light quality of the material demand covered in auto-body also got great attention,this trend has become one of hot research of lightweight material for automobile.High strength 7075-T6 aluminum alloy owns the characteristics of low density and high specific strength,which has attracted the attention of many manufacturers.However,the above materials at room temperature forming poor,compared with the traditional cold forming process,therefore,this paper carried out the experimental study on the 7075-T6 Aluminum Alloy limit forming properties,the main work includes the following aspects: first,to carry out high temperature experimental study on tensile mechanical properties of this type of Aluminum Alloy.DIC optical digital correlation test based on the thermodynamics of the tensile properties of 7075-T6 Aluminum Alloy in RT-450 high temperature range,and analyzes the influence of different temperature on the microstructure and mechanical properties of the alloy,further step,based on thermodynamics of materials tensile test curves obtained,using Field-Backofon(FB)constitutive model to model high temperature flowing stress and strain relationship.The results show that the parameters of the sheet metal under high temperature constitutive model obtained in this paper can well describe the mechanical properties of 7075-T6 aluminum alloy at different temperatures.Secondly,the experimental study on the forming limit of 7075-T6 aluminum alloy under high temperature has been carried out based on the sheet metal forming machine.The forming limit test of 7075-T6 aluminum alloy under iso-thermal working condition was finished by using non contact optical strain measuring system.The forming limit curve of7075-T6 aluminum alloy under typical forming temperature has been obtained,which can provide the relevant evaluation basis for the subsequent B column formability analysis.Further,the thermal formability test and simulation analysis of typical automobile B column parts are carried out.The results show that the conditions of :(blank holder force)BHF,blank size,temperature and lubrication all have important influence on the blankforming of 7075-T6 Aluminum Alloy.This paper determines the 7075-T6 Aluminum Alloy warm forming process,based on performance achieved to meet the needs of the automotive parts,which can provide guidance for the further research and practical application.