The effects of interrupted aging on mechanical properties and corrosion resistance of 7A75 aluminum alloy extruded bar were investigated through various analyses,including electrical conductivity,mechanical properties...The effects of interrupted aging on mechanical properties and corrosion resistance of 7A75 aluminum alloy extruded bar were investigated through various analyses,including electrical conductivity,mechanical properties,local corrosion properties,and slow strain rate tensile stress corrosion tests.Microstructure characterization techniques such as metallographic microscopy,scanning electron microscopy(SEM),and transmission electron microscopy(TEM)were also employed.The results indicate that the tensile strength of the alloy produced by T6I6 aging is similar to that produced by T6I4 aging,and it even exceeds 700 MPa.Furthermore,the yield strength increases by 52.7 MPa,reaching 654.8 MPa after T6I6 aging treatment.The maximum depths of intergranular corrosion(IGC)and exfoliation corrosion(EXCO)decrease from 116.3 and 468.5μm to 89.5 and 324.3μm,respectively.The stress corrosion factor also decreases from 2.1%to 1.6%.These findings suggest that the alloy treated with T6I6 aging exhibits both high strength and excellent stress corrosion cracking resistance.Similarly,when the alloy is treated with T6I4,T6I6 and T6I7 aging,the sizes of grain boundary precipitates(GBPs)are found to be 5.2,18.4,and 32.8 nm,respectively.The sizes of matrix precipitates are 4.8,5.7 and 15.7 nm,respectively.The atomic fractions of Zn in GBPs are 9.92 at.%,8.23 at.%and 6.87 at.%,respectively,while the atomic fractions of Mg are 12.66 at.%,8.43 at.%and 7.00 at.%,respectively.Additionally,the atomic fractions of Cu are 1.83 at.%,2.47 at.%and 3.41 at.%,respectively.展开更多
The effects of the base material(BM)location on the mechanical properties and the exfoliation corrosion performance of friction-stir-welded(FSWed)dissimilar 2024-to-5083 aluminum alloy joints were investigated.Scannin...The effects of the base material(BM)location on the mechanical properties and the exfoliation corrosion performance of friction-stir-welded(FSWed)dissimilar 2024-to-5083 aluminum alloy joints were investigated.Scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),transmission electron microscopy(TEM),tensile tests and electrochemical experiments were conducted.The results revealed that the BM location had little effect on the tensile properties of the joints.The grain orientation spread(GOS)value of 2024 alloy side was lower than that of 5083 alloy side.Intergranular corrosion occurred mainly on the 2024 alloy side,while the grain interior of the 5083 alloy side was corroded due to the higher GOS value and dislocation density.The FSWed dissimilar joints with a superior exfoliation corrosion resistance could be achieved when the 5083 aluminum alloy with better corrosion performance was positioned on the retreating side.展开更多
基金the Tianjin Key Laboratory of Fastening and Connection Technology Enterprises 2022—2023,China(No.TKLF2022-02-C-02)the technical support from the School of Materials Science and Engineering,Central South University,China.
文摘The effects of interrupted aging on mechanical properties and corrosion resistance of 7A75 aluminum alloy extruded bar were investigated through various analyses,including electrical conductivity,mechanical properties,local corrosion properties,and slow strain rate tensile stress corrosion tests.Microstructure characterization techniques such as metallographic microscopy,scanning electron microscopy(SEM),and transmission electron microscopy(TEM)were also employed.The results indicate that the tensile strength of the alloy produced by T6I6 aging is similar to that produced by T6I4 aging,and it even exceeds 700 MPa.Furthermore,the yield strength increases by 52.7 MPa,reaching 654.8 MPa after T6I6 aging treatment.The maximum depths of intergranular corrosion(IGC)and exfoliation corrosion(EXCO)decrease from 116.3 and 468.5μm to 89.5 and 324.3μm,respectively.The stress corrosion factor also decreases from 2.1%to 1.6%.These findings suggest that the alloy treated with T6I6 aging exhibits both high strength and excellent stress corrosion cracking resistance.Similarly,when the alloy is treated with T6I4,T6I6 and T6I7 aging,the sizes of grain boundary precipitates(GBPs)are found to be 5.2,18.4,and 32.8 nm,respectively.The sizes of matrix precipitates are 4.8,5.7 and 15.7 nm,respectively.The atomic fractions of Zn in GBPs are 9.92 at.%,8.23 at.%and 6.87 at.%,respectively,while the atomic fractions of Mg are 12.66 at.%,8.43 at.%and 7.00 at.%,respectively.Additionally,the atomic fractions of Cu are 1.83 at.%,2.47 at.%and 3.41 at.%,respectively.
基金financial supports from the National Natural Science Foundation of China (No.52105357)the Natural Sciences and Engineering Research Council of Canada (NSERC) in the form of international research collaboration,the Natural Science Foundation for Youth of Jiangxi Education Department,China (No.DA202003181)+1 种基金the Foundation of National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology of China (No.EG202103420)the Doctor Starting Foundation of Nanchang Hangkong University,China (No.EA202003208)。
文摘The effects of the base material(BM)location on the mechanical properties and the exfoliation corrosion performance of friction-stir-welded(FSWed)dissimilar 2024-to-5083 aluminum alloy joints were investigated.Scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),transmission electron microscopy(TEM),tensile tests and electrochemical experiments were conducted.The results revealed that the BM location had little effect on the tensile properties of the joints.The grain orientation spread(GOS)value of 2024 alloy side was lower than that of 5083 alloy side.Intergranular corrosion occurred mainly on the 2024 alloy side,while the grain interior of the 5083 alloy side was corroded due to the higher GOS value and dislocation density.The FSWed dissimilar joints with a superior exfoliation corrosion resistance could be achieved when the 5083 aluminum alloy with better corrosion performance was positioned on the retreating side.
