等通道角挤压制备7075铝合金组织及性能研究

Microstructure and properties of 7075 aluminum alloy prepared byequal channel Angle extrusionAbsrtact:The effects of different aging systems on the microstructure and propertiesof 7075 aluminum alloy extruded profiles were studied,and the three aging systemswere compared by mechanical property test,microstructure analysis and peelingcorrosion test,so as to provide references for improving the comprehensive propertiesof 7075 aluminum alloy.Keywords:7075 aluminum alloy;Limitation system;Mechanical properties;Exfoliation corrosion;Metallographic structure.The effect ofsolid solution treatment on microstructure and mechanical properties of 7075aluminum alloy was analyzed.The results show that the size and quantity of coarsesecond phase can be reduced and the solid solution supersaturation of alloyingelements can be improved by using the optimized solid solution technology.The490 C by 2 h+130 C after x 16 h,can significantly improve the mechanicalproperties of aluminum alloy.This kind of product has special shape,thick and thinwall,light weight per unit and strict tolerance requirements.Generally,this kind ofproduct is called aluminum alloy precision (or ultra-precision)profile (pipe),and theproduction technology of this kind of product is called precision (or ultra-precision)extrusion [1].The main characteristics of aluminum alloy special precision (or ultraprecision)extrusion material are:(1)variety,small batch,mostly for special extrusionmaterial,its use almost all walks of life and all aspects of people's lives,including allextrusion products,such as pipes,bars,profiles and wire,involving a variety of alloysand states.Because its section is small,wall is thick thin,weight is light,batch issmall,organize production not easily commonly.(2)complex shape,special contour,mostly shaped,flat wide,with wings,with teeth,porous profile or pipe.The surfacearea of unit volume is large and the production technology is difficult.(3)wide use,special performance and function requirements.In order to meet the requirements ofthe use of products,the choice of alloy state more,almost covered.Precipitation-strengthened 7000 series aluminum alloy has the highest strength amongall commercial aluminum alloys and is widely used in the structural applications ofmilitary,civil aircraft and sporting goods.The 7000 alloy is reinforced by ahigh-density guinier-preston(g-p)region,where strong atomic bonds increaseresistance to dislocation motion.1,2 for al-zn-mg-cu7075 system,after solutiontreatment,aging at low temperature (such as room temperature),high-density g-pregion can be obtained.Cold working usually improves the strength of metals andalloys,but not of 7000 series aluminum alloys.At present,the flat ingot,round ingotand hollow ingot produced at home and abroad almost adopt the semi-continuouscasting,namely IX:method.The casting device is composed of aluminum meltdistributing groove,flow plate,buoy funnel,crystallizer and mobile lifting castingmachine for casting ingots.Due to the strict new requirements for the ingot quality,