Research On Microstructure Andmechanical Properties Of 7075 Aluminum Alloy Sheets Produced By Hot-rolling

7075 aluminum alloy is one of the important powerful alloys with series of advantages such as high specific strength,well machinability,toughness,lower cost and good processing property.They are wiedly used as structural materials in many fields,such as aerospace,architecture and vehicle.We usually product industrial 7075 aluminum alloy by hot rolling process.However,the 7075 aluminum alloy has high strength,so it is hard to be formed and processed.Therefor,the research of hot-rolling process and deformation characteristics can help the development of 7075 aluminum alloy.In this paper,the initial cast and initial forge blank of 7075 aluminum alloy was used.with the multi-pass rolling,the research focused on the microstructure and the mechanical properties of the sheet,the dynamic recrystallization and texture also was investigated.Another way,the heat treatment process meantime was investigated.The following is the mainly conclusions of this paper.Rolling by 5%,11% and 16% reduction per pass,the the initial cast and initial forge sheets' mechanical properties in the RD orientation are both better than in the TD orientation.In the final pass,both of the two initial condition sheets have the similar mechanical properties in RD orientation.Furthermore,with the rolling process,the mechanical properties in TD orientation are increasing,the grain shape is uneven,as fuselage.The microstructures of sheets are conbined by the deformed microstructure and dynamic recrystallization.The final pass sheet's mechanical properties of initial cast blank of 11% reduction per pass is ideal,the yield strength is 322 MPa,the tensile strength is 376 MPa,the elongation is 19%.The three parameters of initial forge sheet in 16% reduchtion are 333 MPa,367MPa,16%.The initial cast blank of 7075 aluminum alloy after rolling is easier to appear dynamic recrystallization.The textures of the sheets after rolling are focused on ? and ? orientation line,besides,the textures from RD orientation turn to TD orientation along with the rolling process.The T6 heat treatment has the better effect to increase the tensile strength and the yield strength of sheets,the initial forge sheet after 16% reduction per pass has the best mechanical properties,the yield strength is 580.91 MPa,the tensile strength is 607.51 MPa,the elongation is 13.62%.The grain orientation of the initial cast sheet after heat treatment is turned from concentrated to dispersion,otherwise,the initial forge sheet hasn't much variety.