The Al-9.2Zn-2.4Mg-1.5Cu aluminum alloy after extrusion was solution treated and aged,where the aging was completed in hydrothermal environment.The microstructure and mechanical properties of the alloy were studied by optical microscope,scanning electron microscope,microhardness tester and universal material tester.The results show that there is no recrystallization in the Al-9.2Zn-2.4Mg-1.5Cu aluminum alloy extrusion sheet after solution treatment,and the grains are still fibrous,though in which there are a lot of subgrain structures and the number of subgrains increases with the increase of solution treatment temperature.Secondly,due to the high content of Zn in the alloy,there are still more low-melting point T phase remaining after homogenization.After extrusion,the low-melting point T phase is distributed in chains along the extrusion direction,and part of the low-melting point T phase redissolves after solution treatment.When the solution treatment temperature is 475 ℃,the tensile strength of the alloy increases first and then decreases with the increase of aging time in hydrothermal environment,the hydrothermal aging time for the peak of the alloy is 10 h,the tensile strength is 733.53 MPa,the yield strength is 694.83 MPa,and the elongation is 13.00％.
关键词
Al-9.2Zn-2.4Mg-1.5Cu铝合金/固溶时效/水热环境/微观组织/力学性能
Key words
Al-9.2Zn-2.4Mg-1.5Cu aluminum alloy/solution treatment and aging/hydrothermal environment/microstructure/mechanical properties
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