| 6000 series aluminum alloy with high strength and high plasticity is an important research topic in the field of metal materials.It has an irreplaceable role in the field of automotive lightweight and aviation.In this paper,9 kinds of aluminum alloy forged material and 3 kinds of aluminum alloy hot pressing materials with different components were prepared by themselves,and the microstructure analysis and tensile properties were measured.The effects of the increase of Mg,Cu,Mn and Mg/Si on the microstructure and properties of the 6000 aluminum alloy were investigated by test,corrosion test,XRD analysis,EBSD analysis and electrical conductivity test,and the effects of the three major alloy elements of Mg,Si and Cu on the microstructure and properties of the 6000 aluminum alloy were studied.The main conclusions are as follows:(1)The effects of the content of Mg elements and the solution and aging process on the microstructure and properties of the aluminum alloy forging press Al-xMg-0.95Si-1.02Cu-0.33Mn-0.015Sr-0.21 Zr are studied when the Mg element is in the 0.941%-1.16% range.The results show that the peak aging strength of the alloy is greater than that of 405 MPa and the elongation is above 10% when the alloy composition is in this range.The tensile properties of the alloy are very excellent.The increase of Mg content has little effect on the grain size,tensile strength,elongation and corrosion resistance of the alloy,which will decrease the conductivity of the alloy and the ability to resist the intercrystalline corrosion,and increase the hardness of the alloy.The optimum solution temperature of the three alloys to obtain the best mechanical properties is 540 ?,the optimum aging temperature is between 180 ? and-190 ?,and the higher aging temperature should be selected with the increase of Mg content,and the optimum aging time is 4H.The peak aging strength of alloy forging material Al-0.94Mg-0.95Si-1.02Cu-0.33Mn-0.023Sr-0.21 Zr reaches 422.27 Mpa and the elongation is 11.16%.(2)The effects of the content of Cu elements and the solution and aging process on the microstructure and properties of the aluminum alloy forging press Al-0.98Mg-1Si-xCu-0.335Mn-0.2Zr-0.015 Sr are studied when the Cu element is in the 1.0%-1.25% range.The results show that the peak aging strength of the alloy is greater than that of 410 MPa and the elongation is above 10% when the alloy composition is within this range.The extension performance of the alloy is very excellent,and the increase of Cu content has little effect on the corrosion resistance of the alloy;the elongation,electrical conductivity and intergranular corrosion resistance of the alloy are decreased,and the grain size,tensile strength,hardness and overfiring sensitivity of the alloy are increased.The optimum solution temperature of the two alloys to obtain the best mechanical properties is 540 ?,the optimum aging temperature is between 180 ? and-190 ?,and the lower aging temperature should be selected with the increase of Cu content.The optimum aging time is between 4h-6h and the lower time effect temperature should be selected with the increase of Cu content.The peak aging strength of alloy forging material Al-0.97Mg-0.99Si-1.25Cu-0.33Mn-0.014Sr-0.21 Zr reaches 431.23 Mpa and the elongation is 13.56%.(3)The effects of the increase of Mg,Si and Cu alloy elements on the microstructure and properties of Al-xMg-ySi-zCu-0.335Mn-0.2Zr-0.020 Sr were studied at the same time of Mg/Si.The results showed that the peak aging strength of the alloy was greater than 410 MPa and the elongation rate was 10%,and the tensile properties were excellent.The increase of gold element has little effect on the grain size and resistance to exfoliation corrosion of the alloy,and decreases the elongation,electrical conductivity and intergranular corrosion resistance of the alloy,and increases the hardness of the alloy.The strength of the alloy does not increase monotonically with the increase of the main alloy elements.When the content of Mg is 1.24%,the content of Si is greater than 1.25%,and the content of Cu is greater than 1.03%,the addition of these three elements will reduce the tensile strength of the alloy.The best solution temperature of the four alloys with the best mechanical properties is 540 ?,the optimum aging temperature is between 180 ? and-190 ?,and the lower aging temperature should be selected with the increase of the content of three major alloy elements.The optimum aging time is between 4h-8h and the lower aging time should be selected with the increase of the content of the three main alloying elements.Temperature.The peak aging strength of alloy forging material Al-1.24Mg-1.26Si-1.03Cu-0.33Mn-0.020Sr-0.20 Zr reaches 425.05 MPa and the elongation is 10.76%.(4)The effect of the content of Mn element on the microstructure and properties of the aluminum alloy hot press material Al-0.91Mg-0.81Si-1.02Cu-xMn-0.2Zr-0.02 Sr is studied when the Mn element is in the 0%-1.061%.The result shows that the increase of the Mn element can greatly refine the grain of the alloy and make the equiaxial degree of the grain of the alloy decrease,but the Mn element content is greater than that of the alloy after the element content is greater than the content of the element.The addition of Mn has little effect on the grain size of the alloy.At the same time,the increase of Mn will obviously reduce the tensile strength of the alloy.The increase of Mn element has little effect on the anti peeling corrosion resistance of the alloy,but it will greatly improve the intercrystalline corrosion resistance of the alloy.The effect of Mn elements on the tensile properties,grain size and corrosion resistance of the alloy is considered.In order to refine the grain of the 6000 series aluminum alloy,the addition of about 0.7% Mn elements in the alloy is more reasonable.(5)A comprehensive comparison of the small angle grain boundary ratio in the EBSD data of the nine aluminum alloy forged materials and the data of the intercrystalline corrosion resistance of the alloy can be found that the higher the proportion of the grain boundary in the middle and small angles of the 6000 system aluminum alloy,the lower the intercrystalline corrosion ability of the alloy,which is completely opposite to the 7000 system.In this paper,it is found for the first time that the larger the difference in the alloy composition and the same heat treatment process in the 6000 series aluminum alloy,the worse the grain boundary proportion of the alloy is in the small angle of the alloy,the worse the anti crystal corrosion resistance of the alloy is,which is completely opposite to the law of the 7000 system alloy.At the same time,the Mg content,the content of Mn,the content of Mn and the Mg of the Mg/Si are also studied.The total content of three main alloy elements,Si and Cu and the effect of heat treatment on the microstructure and properties of the 6000 series aluminum alloys provide a theoretical basis for the development of the new 6000 series aluminum alloy. |
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