均匀化退火对7A04铝合金挤压材显微组织的影响
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摘要
利用OM、SEM、TEM、EBSD等手段研究了均匀化退火冷却方式对7A04铝合金挤压材显微组织的影响。结果表明,7A04铝合金均匀化退火的冷却方式对基体上的第二相种类和分布特征影响显著。均匀化退火水冷、油冷、空冷坯料的第二相数量较少,炉冷的坯料第二相较多,由少量粗大的Al_2CuMg、Al_7Cu_2Fe和大量弥散分布的针状MgZn_2相组成,同时随着均匀化冷却速率的降低,粗大第二相的含量先增加后降低,其中炉冷至250℃空冷时,第二相含量达到最大值,约为17.5%。粗大第二相较多坯料在后续热挤压时,粗大第二相作为再结晶形核位置,促进动态再结晶;又由于析出的细小析出相钉扎晶界,阻碍再结晶晶粒的长大。因此,炉冷坯料挤压后固溶时效的挤压材比水冷坯料挤压材晶粒尺寸显著减小。
The effect of homogenizing annealing cooling on the microstructure of extruded 7A04 aluminium alloy is researched through OM, SEM, TEM, EBSD and so on. The results show that, the cooling method of 7A04 aluminum alloy homogenizing annealing has a significant effect on the type and distribution characteristics of the second phase on the matrix. The number of the second phase in the furnace-cooled billets after homogenization annealing is more than that of the second phase in the water-cooled, oil-cooled and air-cooled billets, which consists of a small amount of coarse Al_2CuMg, Al_7Cu_2Fe and a large amount of dispersed needle-shaped MgZn_2 phases. At the same time, with the decrease of homogenization cooling rate, the content of the coarse second phase first increases and then decreases. When the temperature of furnace is cooled to 250℃ and then air cooling, the content of second phases reaches the maximum value, about 17.5%. During subsequent hot extrusion, the coarse second phase acts as the recrystallization nucleation position to promote dynamic recrystallization, and the fine precipitated phase pins the grain boundary, which hinders the growth of recrystallized grains. Therefore, the grain size of extrusion after solution ageing is significantly smaller than that of water-cooled extrusion.
The effect of homogenizing annealing cooling on the microstructure of extruded 7A04 aluminium alloy is researched through OM, SEM, TEM, EBSD and so on. The results show that, the cooling method of 7A04 aluminum alloy homogenizing annealing has a significant effect on the type and distribution characteristics of the second phase on the matrix. The number of the second phase in the furnace-cooled billets after homogenization annealing is more than that of the second phase in the water-cooled, oil-cooled and air-cooled billets, which consists of a small amount of coarse Al_2CuMg, Al_7Cu_2Fe and a large amount of dispersed needle-shaped MgZn_2 phases. At the same time, with the decrease of homogenization cooling rate, the content of the coarse second phase first increases and then decreases. When the temperature of furnace is cooled to 250℃ and then air cooling, the content of second phases reaches the maximum value, about 17.5%. During subsequent hot extrusion, the coarse second phase acts as the recrystallization nucleation position to promote dynamic recrystallization, and the fine precipitated phase pins the grain boundary, which hinders the growth of recrystallized grains. Therefore, the grain size of extrusion after solution ageing is significantly smaller than that of water-cooled extrusion.
引文
1刘兵,彭超群,王日初,等.大飞机用铝合金的研究现状及展望[J].中国有色金属学报,2010,20(9):1705~1715
2张坤,赵晓东,陈慧琴,等.温度对Al-Zn-Mg-Cu高强铝合金静态回复力学行为的影响[J].航空材料学报,2017,37(3):37~43
3 Wiilliams J C,Edgar A,Srake J R.Progress in structural materials for aerospace systems[J].Acta Materialia,2003,51(19):5775~5799
4梁岩,孙荣滨.7A04铝合金铸锭均匀化热处理研究[J].轻合金加工技术,2008,36(8):9~14
5 Wen Kai,Xiong Baiqing,Zhang Yonggan,et al.Microstructure evolution of a high zinc containing Al-Zn-Mg-Cu alloy during homogenization[J].Rare Metal Materials and Engineering,2017,46(4):0928~0934
6鲁法云,赵凤,穆楠,等.7050铝合金均匀化过程中组织转变[J].材料热处理学报,2015,36(5):17~23
7 Liu Shengdan,You Jianghai,Zhang Xinming,et al.Fluence of cooling rate after homogenization on the flow behavior of aluminum alloy 7050 under hot compression[J].Materials Science and Engineering A,2010,527(4-5):1200~1205
8张新明,袁玉宝,刘文军,等.均匀化后冷却方式对7050铝合金热压缩流变行为的影响[J].中南大学学报(自然科学版),2009,40(3):626~631
9 Yang Qunying,Deng Zanhui,Zhang Zhiqing,et al.Effects of strain rate on flow stress behavior and dynamic recrystallization mechanism of Al-Zn-Mg-Cu aluminum alloy during hot deformation[J].Materials Science and Engineering A,2016,662:204~213
10彭祥阳,郭明星,汪小锋,等.不同尺寸粒子对Al-Mg-Si-Cu系合金组织、织构和力学性能的影响[J].金属学报,2015,51(2):169~177
11 Robson J D,Henry D T,Davis B.Particle effects on recrystallization in magnesium-manganese alloys:Particle-stimulated nucleation[J].Acta Materialia,2009,57(9):2739~2747
12 Xu Xiaofeng,Zhao Yuguang,Wang Xudong,et al.Effect of rapid solid-solution induced by electropulsing on the microstructure and mechanical properties in 7075 Al alloy[J].Materials Science and Engineering A,2016,654:278~281
13舒文祥,侯陇刚,刘君城,等.先进高强韧Al-Zn-Mg-Cu合金凝固和均匀化组织及相构成[J].北京科技大学学报,2014(11):1534~1539
14 Zhang Zhihao,Xue Jie,Jiang Yanbin.Enhanced homogeneities of microstructure and property in Al-Zn-Mg-Cu extruded product by cooling rate after homogenization treatment[J].Journal of Materials Engineering&Performance,2017,26(19):1~8
15许晓静,张允康,邓平安,等.预退火对7085铝合金挤压材组织和性能的影响[J].材料热处理学报,2014,35(8):36~40
16 Zhang Zhihao,Xue Jie,Jiang Yanbin,et al.Effect of pre-annealing treatment on the microstructure and mechanical properties of extruded Al-Zn-Mg-Cu alloy bars[J].International Journal of Minerals,Metallurgy and Materials,2017,24(11):1284~129
2张坤,赵晓东,陈慧琴,等.温度对Al-Zn-Mg-Cu高强铝合金静态回复力学行为的影响[J].航空材料学报,2017,37(3):37~43
3 Wiilliams J C,Edgar A,Srake J R.Progress in structural materials for aerospace systems[J].Acta Materialia,2003,51(19):5775~5799
4梁岩,孙荣滨.7A04铝合金铸锭均匀化热处理研究[J].轻合金加工技术,2008,36(8):9~14
5 Wen Kai,Xiong Baiqing,Zhang Yonggan,et al.Microstructure evolution of a high zinc containing Al-Zn-Mg-Cu alloy during homogenization[J].Rare Metal Materials and Engineering,2017,46(4):0928~0934
6鲁法云,赵凤,穆楠,等.7050铝合金均匀化过程中组织转变[J].材料热处理学报,2015,36(5):17~23
7 Liu Shengdan,You Jianghai,Zhang Xinming,et al.Fluence of cooling rate after homogenization on the flow behavior of aluminum alloy 7050 under hot compression[J].Materials Science and Engineering A,2010,527(4-5):1200~1205
8张新明,袁玉宝,刘文军,等.均匀化后冷却方式对7050铝合金热压缩流变行为的影响[J].中南大学学报(自然科学版),2009,40(3):626~631
9 Yang Qunying,Deng Zanhui,Zhang Zhiqing,et al.Effects of strain rate on flow stress behavior and dynamic recrystallization mechanism of Al-Zn-Mg-Cu aluminum alloy during hot deformation[J].Materials Science and Engineering A,2016,662:204~213
10彭祥阳,郭明星,汪小锋,等.不同尺寸粒子对Al-Mg-Si-Cu系合金组织、织构和力学性能的影响[J].金属学报,2015,51(2):169~177
11 Robson J D,Henry D T,Davis B.Particle effects on recrystallization in magnesium-manganese alloys:Particle-stimulated nucleation[J].Acta Materialia,2009,57(9):2739~2747
12 Xu Xiaofeng,Zhao Yuguang,Wang Xudong,et al.Effect of rapid solid-solution induced by electropulsing on the microstructure and mechanical properties in 7075 Al alloy[J].Materials Science and Engineering A,2016,654:278~281
13舒文祥,侯陇刚,刘君城,等.先进高强韧Al-Zn-Mg-Cu合金凝固和均匀化组织及相构成[J].北京科技大学学报,2014(11):1534~1539
14 Zhang Zhihao,Xue Jie,Jiang Yanbin.Enhanced homogeneities of microstructure and property in Al-Zn-Mg-Cu extruded product by cooling rate after homogenization treatment[J].Journal of Materials Engineering&Performance,2017,26(19):1~8
15许晓静,张允康,邓平安,等.预退火对7085铝合金挤压材组织和性能的影响[J].材料热处理学报,2014,35(8):36~40
16 Zhang Zhihao,Xue Jie,Jiang Yanbin,et al.Effect of pre-annealing treatment on the microstructure and mechanical properties of extruded Al-Zn-Mg-Cu alloy bars[J].International Journal of Minerals,Metallurgy and Materials,2017,24(11):1284~129