Microstructure Control And Properties Of Continuous Extrusion Aluminum Alloy During Heat Treatment And Plastic Deformation

Continuous extruding aluminum alloy is widely used in construction,automobile,aerospace and electronic appliances due to its uniform structure and good performance.In this paper,the microalloying and heat treatment process of aluminum alloy extruding plate were explored,and the microstructure and performance of the aluminum alloy were improved.The effect of microalloying on microstructure and mechanical properties of aluminum alloy was analyzed by using scanning electron microscope(SEM),electron backscatter diffraction(EBSD),metallographic microscope(OM)and tensile testing machine,and the heat treatment of aluminum alloy after microalloying was studied.In addition,the solid solution and single stage aging treatment system of Al-Mg-Si-Zr alloy were studied by using hardness and conductivity test,microstructure contrast analysis and stress-strain curve analysis.The mechanical properties of the Al-Mg-Si-Zr alloy have been improved to a certain extent under the effect of fine grain strengthening and dispersion strengthening.The air-cooled cooling way is used in the process of production,and then after 150℃/40 min of preaging treatment,can make the elongation reached a maximum of 21.8%.The hardness of Al-Mg-Si-Zr alloy after preaging can reach up to 120HV.In order to ensure that the hardness of Al-Mg-Si-Zr alloy extruded plate was reduced to 60HV,the optimal heat treatment process of 560℃ solid solution for 12h(air cooling)+160℃ low temperature aging was determined.In the present work,the micro structural evolution and mechanical properties of Al-Zn-Mg-Cu alloy after friction stir processing(FSP)electron back scattering diffraction(EBSD),metallographic microscope(OM),transmission electron microscopy(TEM)and performance test.The results show that FSP exerted a remarkable effect on grain refinement of the alloys;changing typical hot-rolled structure consisted of large elongated pancake shaped grains into a fine equiaxed grain structure.Such effect was found to be related to the occurrence of continuous dynamic recrystallization(CDRX).In addition,an attractive mechanical property of Al-Zn-Mg-Cu alloy subjected to FSP was obtained.