李佳乐等：半连续铸造7136超高强铝合金的组织特征及均匀化处理工艺 ·921· 级均匀化，非平衡晶间相明显减少，晶间只有少量 ℃~463℃较理想.但在462℃随保温时间的延长， Fe元素聚集，应该是Al,Cu,Fe相高熔点相，对应着 对提高均匀化效果作用不大. 图12中差示扫描量热法获取的曲线中的第二个峰. (3)7136铝合金经过450℃，24h+470℃，24h 表4图11中各点能谱分析 双级均匀化，差示扫描量热法峰值已经很小，晶间除 Table 4 Spectrum analysis of each point in Fig.11 了少量高熔点Al,Cu2Fe相残留，其他相已基本消 位置 Al Mg Zn Cu Fe 除，均匀化效果显著 1 54.88 1.18 4.22 35.464.26 2 62.54 1.33 6.86 27.31 1.96 参考文献 3 59.26 1.78 2.84 32.32 3.80 [1]Immarigeon JP,Holt RT,Koul A K,et al.Lightweight materials 4 62.13 1.48 3.46 27.12 5.81 for aircraft applications.Mater Charact,1995,35(1):41 [2]Williams J C,Starke Jr E A.Progress in structural materials for aerospace systems.Acta Mater,2003,51(19):5775 ---·铸态 477.41 1.0 -462℃.24h [3]Starke Jr E A,Staley J T.Application of modern aluminum alloys 450℃.24h+470℃.24h to aireraft.Prog Aerosp Sci,1996,32(2-3):131 [4]Jia P F.Cao Y H,Geng Y D,et al.Effects of d.c.current on the 0.5 phase transformation in 7050 alloy during homogenization.Mater Charact,2014,96:21 [5]Liu J,Kulak M.A new paradigm in the design of aluminum alloys 477.40 for aerospace applications.Mater Sci Forum,2000,331-337:127 [6]Shu W X,Liu J C,Hou L G,et al.Microstructural evolution of 475.48 Al-8.59Zn-2.00Mg-2.44Cu during homogenization.Int J Miner 05 Metall Mater,2014,21(12):1215 200 400 600 温度℃ [7]Li L,Deng ZZ,Han Y,et al.Study on cast and homogenized microstructure of a new super-high strength aluminum alloy.Light 图12铸态，单级均匀化和双级均匀化后的差示扫描量热法曲线 Alloy Fabric Technol,2011,39(12):20 Fig.12 DSC curves after as-cast,single-stage homogenization and (李炼，邓桢桢，韩逸，等.新型超高强铝合金铸态及均匀化 two-stage homogenization 态组织研究.轻合金加工技术，2011,39(12)：20) [8]Robson J D.Microstructural evolution in aluminium alloy 7050 Cu元素的扩散系数小于Mg元素和Zn元素 during processing.Mater Sci Eng A,2004.382(1-2):112 扩散系数可用Arrhenius关系进行计算：D=D。exp [9]Yang X B,Chen J H,Liu J Z,et al.Spherical constituent parti- (-Q/RT),其中D为扩散系数，D。为扩散常量，Q cles formed by a multistage solution treatment in Al-Zn-Mg-Cu 为扩散的活化能，R为气体常数. alloys.Mater Charact,2013,83:79 [10]Xiao T,Deng Y L,Ye L Y,et al.Effect of three-stage homoge- 对于Cu、Mg和Zn元素分别为D=4.8×10-5 nization on mechanical properties and stress corrosion cracking of exp(-16069/T)、D=6.23×10-exp(-13831/T)、 Al-Zn-Mg-Zr alloys.Mater Sci Eng A,2016,675:280 D=2.45×10-5exp(-14385/T)[],在实验加热及 [11]Mahathaninwong N,Plookphol T.Wannasin J,et al.T6 heat 保温的温度范围内，相同温度条件下Cu元素、Mg元 treatment of rheocasting 7075 Al alloy.Mater Sci Eng A,2012, 532:91 素和Zn元素的扩散系数大小为Cu<Mg<Zn.正是由 [12]Jia P F,Cao Y H,Geng Y D,et al.Studies on the microstruc- 于Cu元素扩散系数非常小且有高熔点AL,Cu,Fe晶间 tures and properties in phase transformation of homogenized 7050 相存在，使得Cu元素品间含量要高于品内. alloy.Mater Sci Eng A.2014,612:335 [13]LiJ F,Peng Z W,Li C X,et al.Mechanical properties,corro- 3结论 sion behaviors and microstructures of 7075 aluminium alloy with various aging treatments.Trans Nonferrous Met Soc China,2008, (1)半连续铸造7136铝合金铸态组织没有明 18(4):755 显的层片状α(A)+T共晶相的特征，也没有发现S [14]Liu Y,Jiang D M,Xie WL,et al.Solidification phases and their 相的存在.Cu元素在品间偏聚，Mg和Zn元素以 evolution during homogenization of a DC cast Al-8.35Zn- 2.5Mg-2.25Cu alloy.Mater Charact,2014,93:173 MgZn,相形式弥散分布在晶内. [15]Wen K,Xiong B Q,Fan Y Q,et al.Transformation and dissolu- (2)采用455~469℃保温24h的单级均匀化工 tion of second phases during solution treatment of an Al-Zn-Mg- 艺，随温度的升高，非平衡品间相先减少后增多，461 Cu alloy containing high zinc.Rare Met,2018,37(5):376李佳乐等: 半连续铸造 7136 超高强铝合金的组织特征及均匀化处理工艺 级均匀化,非平衡晶间相明显减少,晶间只有少量 Fe 元素聚集,应该是 Al 7 Cu2Fe 相高熔点相,对应着 图 12 中差示扫描量热法获取的曲线中的第二个峰. 表 4 图 11 中各点能谱分析 Table 4 Spectrum analysis of each point in Fig. 11 位置 Al Mg Zn Cu Fe 1 54郾 88 1郾 18 4郾 22 35郾 46 4郾 26 2 62郾 54 1郾 33 6郾 86 27郾 31 1郾 96 3 59郾 26 1郾 78 2郾 84 32郾 32 3郾 80 4 62郾 13 1郾 48 3郾 46 27郾 12 5郾 81 图12 铸态、单级均匀化和双级均匀化后的差示扫描量热法曲线 Fig. 12 DSC curves after as鄄cast, single鄄stage homogenization and two鄄stage homogenization Cu 元素的扩散系数小于 Mg 元素和 Zn 元素. 扩散系数可用 Arrhenius 关系进行计算:D = D0 exp ( - Q/ RT),其中 D 为扩散系数,D0 为扩散常量,Q 为扩散的活化能,R 为气体常数. 对于 Cu、Mg 和 Zn 元素分别为 D = 4郾 8 伊 10 - 5 exp( - 16069 / T)、D = 6郾 23 伊 10 - 6 exp( - 13831 / T)、 D = 2郾 45 伊 10 - 5 exp( - 14385 / T) [15] ,在实验加热及 保温的温度范围内,相同温度条件下 Cu 元素、Mg 元 素和 Zn 元素的扩散系数大小为 Cu <Mg <Zn. 正是由 于 Cu 元素扩散系数非常小且有高熔点 Al 7Cu2Fe 晶间 相存在,使得 Cu 元素晶间含量要高于晶内. 3 结论 (1)半连续铸造 7136 铝合金铸态组织没有明 显的层片状 琢(Al) + T 共晶相的特征,也没有发现 S 相的存在. Cu 元素在晶间偏聚,Mg 和 Zn 元素以 MgZn2 相形式弥散分布在晶内. (2)采用455 ~ 469 益保温24 h 的单级均匀化工 艺,随温度的升高,非平衡晶间相先减少后增多,461 益 ~ 463 益较理想. 但在 462 益随保温时间的延长, 对提高均匀化效果作用不大. (3)7136 铝合金经过 450 益 ,24 h + 470 益 ,24 h 双级均匀化,差示扫描量热法峰值已经很小,晶间除 了少量高熔点 Al 7 Cu2Fe 相残留,其他相已基本消 除,均匀化效果显著. 参 考 文 献 [1] Immarigeon J P, Holt R T, Koul A K, et al. Lightweight materials for aircraft applications. Mater Charact, 1995, 35(1): 41 [2] Williams J C, Starke Jr E A. Progress in structural materials for aerospace systems. Acta Mater, 2003, 51(19): 5775 [3] Starke Jr E A, Staley J T. Application of modern aluminum alloys to aircraft. Prog Aerosp Sci, 1996, 32(2鄄3): 131 [4] Jia P F, Cao Y H, Geng Y D, et al. Effects of d. c. current on the phase transformation in 7050 alloy during homogenization. Mater Charact, 2014, 96: 21 [5] Liu J, Kulak M. A new paradigm in the design of aluminum alloys for aerospace applications. Mater Sci Forum, 2000, 331鄄337: 127 [6] Shu W X, Liu J C, Hou L G, et al. Microstructural evolution of Al鄄鄄8郾 59Zn鄄鄄2郾 00Mg鄄鄄2郾 44Cu during homogenization. Int J Miner Metall Mater, 2014, 21(12): 1215 [7] Li L, Deng Z Z, Han Y, et al. Study on cast and homogenized microstructure of a new super鄄high strength aluminum alloy. Light Alloy Fabric Technol, 2011, 39(12): 20 (李炼, 邓桢桢, 韩逸, 等. 新型超高强铝合金铸态及均匀化 态组织研究. 轻合金加工技术, 2011, 39(12): 20) [8] Robson J D. Microstructural evolution in aluminium alloy 7050 during processing. Mater Sci Eng A, 2004, 382(1鄄2):112 [9] Yang X B, Chen J H, Liu J Z, et al. Spherical constituent parti鄄 cles formed by a multistage solution treatment in Al鄄鄄 Zn鄄鄄 Mg鄄鄄 Cu alloys. Mater Charact, 2013, 83: 79 [10] Xiao T, Deng Y L, Ye L Y, et al. Effect of three鄄stage homoge鄄 nization on mechanical properties and stress corrosion cracking of Al鄄鄄Zn鄄鄄Mg鄄鄄Zr alloys. Mater Sci Eng A, 2016, 675: 280 [11] Mahathaninwong N, Plookphol T, Wannasin J, et al. T6 heat treatment of rheocasting 7075 Al alloy. Mater Sci Eng A, 2012, 532: 91 [12] Jia P F, Cao Y H, Geng Y D, et al. Studies on the microstruc鄄 tures and properties in phase transformation of homogenized 7050 alloy. Mater Sci Eng A, 2014, 612: 335 [13] Li J F, Peng Z W, Li C X, et al. Mechanical properties, corro鄄 sion behaviors and microstructures of 7075 aluminium alloy with various aging treatments. Trans Nonferrous Met Soc China, 2008, 18(4): 755 [14] Liu Y, Jiang D M, Xie W L, et al. Solidification phases and their evolution during homogenization of a DC cast Al鄄鄄 8郾 35Zn鄄鄄 2郾 5Mg鄄鄄2郾 25Cu alloy. Mater Charact, 2014, 93: 173 [15] Wen K, Xiong B Q, Fan Y Q, et al. Transformation and dissolu鄄 tion of second phases during solution treatment of an Al鄄鄄Zn鄄鄄 Mg鄄鄄 Cu alloy containing high zinc. Rare Met, 2018, 37(5): 376 ·921·