METALS AND METAL MARTIX COMPOSITES |
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Effects of Aging Stress on the Mechanical Properties and Exfoliation CorrosionResistance of 7A04 Aluminum Alloy with Two-stage Aging |
LI Hu1, ZHAO Junwen1,2, WANG Chaoqun1, GUO An1, LI Hengkui3, DAI Guangze1,2
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1 School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 2 Yangzhou Fengze Rail Technologies Co. Ltd., Yangzhou 225200 3 CRRC Qingdao Sifang Co. Ltd., Qingdao 266111 |
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Abstract Effects of aging stress on the mechanical properties and exfoliation corrosion resistance of 7A04 aluminum alloy with two-stage aging were investigated by mechanical properties test, XRD analysis, tensile fracture surface analysis and exfoliation corrosion evaluation. The results indicated that the strength and hardness of 7A04 aluminum alloy increased with the aging stress of 100~300 MPa. Compared with no stress-aging condition, the tensile strength, yield strength and hardness of 7A04 aluminum alloy reached 652.3 MPa, 588.5 MPa and 178HB after aged with stress of 200 MPa, increased by 4.47%, 3.94% and 5.95% respectively, but the change of the elongation is insignificant. Additionally, with the increase of aging stress, the content of MgZn2 precipitates in the microstructure of the alloy increased, and the fracture mode of the alloy also changed. The suitable aging stress can reduce the exfoliation corrosion sensitivity of 7A04 aluminum alloy, and the alloy has the best corrosion resistance with the aging stress of 200 MPa, which reached the level of EA.
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Published: 31 May 2019
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Fund:This work was financially supported by the National Key Technology R & D Program of China (2015BAG12B01). |
About author:: Hu Lireceived his M.S. degree in June 2018 from Southwest Jiaotong University in engineering. From September 2015 to April 2018, he learned at School of Materials Science and Engineering, focusing on the research of stress aging heat treatment of high strength aluminum alloy.Junwen Zhaoreceived his Ph.D. degree in material processing engineering from Huazhong University of Science and Technology in 2009. He is a member of China Metal Society and Sichuan Foundry Society, and he is currently an associate professor in School of Materials Science and Engineering. His research interests are alloys and composite materials, focusing on metal semi-solid processing technology. |
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