双级固溶对高 Zn 含量Al-Zn-Mg-Cu合金组织及力学性能的影响

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Effect of dual stage solid solution on the microstructure and mechanical properties of Al-Zn-Mg-Cu alloy with high Zn content

WANG Zhuo1，²，WANG Yizhe1，²，WANG Jiaxing1，²，LIU Zihan 1，2 ， ZHOU Junye ⋅1，2 LIU Ying1'²，YANG Xiao1，²，WANG Liwei1，2

（1.School of Materials Science and Engineering，Hebei University of Science and Technology， Shijiazhuang，Hebei O50o18，China; 2.Hebei Key Laboratory of Material Near-NetForming Technology，Shijiazhuang，Hebei O50ol8，China）

Abstract：Inordertosolve the problemofdificult dissolutionof second phaseparticlescaused byexcessve high Zncontent duringthe traditional heat treatment of Al- Zn-Mg-Cu alloy，the effects of different two-stage solid solution processes on the microstructure and mechanical properties of theas-quenchedand T6aged Al-Zn-Mg-Cualloy with high Zn content were investigated by using optical microscope（OM），scanning electron microscope（SEM），Vickers hardness tester and tensile testingunder room temperature.Theresultsshow that withthe increaseof the first-stage solid solution temperature，the strengthandhardnessof thealloyincrease，and theoverallmechanicalpropertiesofthematerialsimprove.Theelongationrate of thealloy increasesfirstlyandthendecreases withtheincreaseof thefirst-stagesolid solution temperature，andthetensile fractureshows toughnessfracture.Afterthealoysubjecting toatwo-step solution heat treatmentandquenching processat 460∘C for 1h and then at 475∘° for 2h ，thetensile strength，yield strength and elongation of the alloyare 580.5MPa ， 465.3MPa and 13.6% ，respectively，indicating good comprehensive mechanical properties. The modulation of the temperature within the first stageof the two-stage solution treatment processisconducivetotheamelioration of the comprehensiveperformanceofaluminumaloymaterialswithahigh Zncontent.Itcanprovide theoreticalreference for improving the heat treatment process of aluminum alloy materials.

Keywords： the organization，structure， defects，and propertiesof materials；Al-Zn-Mg-Cu aloy;microstructure; solid solution；tensile property；fracture morphology

Al-Zn-Mg-Cu合金具有轻质高强、熔点低、流动性好、铸造性能佳和耐磨性高等特点，广泛应用于航空航天和高速列车等领域[1-2]。（剩余12344字）