Effect of cryogenic rolling and aging heat treatment on microstructure and properties of Al-Zn-Mg aluminum alloy
CHEN Songyi1,2,3, LIU Qiang1,3, CHEN Kanghua1,2,3, HUANG Lanping2
1. Light Alloy Research Institute, Central South University, Changsha 410083, China; 2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China; 3. Collaborative Innovation Center of Advance Nonferrous Structural Materials and Manufacturing,Central South University, Changsha 410083, China
Abstract：The Al-Zn-Mg alloy sheets were aged by CR (cryogenic rolling)+480h natural aging, CR+100 ℃/12 h aging, CR+100 ℃/80 h aging and 100 ℃/107 h aging treatment for solution-quenched sheets without CR, respectively. The hardness and room temperature tensile properties of the alloys were determined,and exfoliation corrosion (EXCO) and electrochemical corrosion were carried out. The morphology and microstructure of Al-Zn-Mg alloys were observed by optical microscope, scanning electron microscope and transmission electron microscope. The effects of cryogenic rolling and different aging treatment (natural aging and different time artificial aging) on the micro-structure and properties of Al-Zn-Mg alloys were studied. The results show that the EXCO resistance and electrochemical corrosion resistance of CR+480 h natural aging and CR+100 ℃/12 h ageing treated alloys are worse than those of solution-quenched alloys treated directly at 100 ℃/107 h. The main reason is the formation of submicron, fibrous and high dislocation density ultrafine grains during cryogenic rolling. CR+100 ℃/80 h aging treatment alloy has better exfoliation corrosion resistance and electrochemical corrosion properties due to the formation of high density dislocations during cryogenic rolling, and coarse and discontinuous grain boundary precipitates are formed after subsequent 100 ℃/80 h aging treatment. In addition, the ultra-fine grain structure with high dislocation density was formed after cryogenic rolling, which significantly accelerated the aging hardening response.
陈送义, 刘强, 陈康华, 黄兰萍. 低温轧制及时效热处理对Al-Zn-Mg铝合金显微组织与性能的影响[J]. 粉末冶金材料科学与工程, 2020, 25(1): 16-26.
CHEN Songyi, LIU Qiang, CHEN Kanghua, HUANG Lanping. Effect of cryogenic rolling and aging heat treatment on microstructure and properties of Al-Zn-Mg aluminum alloy. Materials Science and Engineering of Powder Metallurgy, 2020, 25(1): 16-26.
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2020, Vol. 25 
