7020铝合金经470℃固溶1 h后分别进行自然时效0 h、168 h以及65℃预时效72 h、168 h，再进行(90℃，8 h)+(160℃，14 h)双级时效。采用室温拉伸、慢应变速率拉伸(SSRT)、扫描电镜(SEM)、透射电镜(TEM)研究预时效工艺对7020铝合金的常温拉伸性能、抗应力腐蚀性能与显微组织的影响。结果表明：经65℃、168 h预时效处理后，合金具有最高的抗拉强度Rm=397.4 MPa和最好的抗应力腐蚀性能ISSRT=?0.003；65℃、72 h预时处理效和自然时效168 h后合金的抗拉强度和抗应力腐蚀性能相当，Rm、ISSRT分别为387.6 MPa、0.034和392.0 MPa、0.036；而直接双级时效合金的抗拉强度和抗应力腐蚀性能最差，Rm、ISSRT为368.9 MPa、0.038。晶内析出相η′(MgZn2)的尺寸随预时效时间的延长而减小，晶界析出相η(MgZn2)的断续分布程度随预时效时间延长而增大。
After solution heat treatment at 470℃for 1h, the alloys were natural aged for 0hor168h and pre-aged at 65℃for 72hor168h, respectively. And then,the two-step aging ((90℃,8h)+(160℃,14h)) was conducted on these alloys. The effect of pre-ageing treatment on the tensile properties, resistances to stress corrosion and microstructures of 7020 aluminum alloy was investigated by tensile test, slow strain rate tensile (SSRT) test, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). 7020 aluminum alloy aged at 65℃for168h pre-ageing treatment has the highest tensile propertyRmof 397.4 MPa as well as the best stresscorrosion resistanceISSRTof ?0.003. The tensile property and stress corrosion resistance of alloy pre-ageing treatment at 65℃for72h are 387.6 MPa and 0.034. And it is comparable of that of natural aging 168h, withRmof 392.0 MPa andISSRTof 0.036. While the tensile property and stress corrosion resistance of alloy by direct two-step aging are the worst, withRmof 368.9 MPa andISSRTof 0.038. With the increase ofthepre-aging time, the size of intragranular precipitatesη′(MgZn2) inside grains decreases,the intermittent distribution degree of precipitates intragranular precipitatesη′(MgZn2) inside grains decreasesand the intermittent distribution degree of precipitatesη(MgZn2) at the grain boundaries increases.
参考文献
| [1] | Wang, D;Ni, DR;Ma, ZY.Effect of pre-strain and two-step aging on microstructure and stress corrosion cracking of 7050 alloy[J].Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing,20081/2(1/2):360-366. |
| [2] | A. Heinz;A. Haszler;C. Keidel;S. Moldenhauer;R. Benedictus;W. S. Miller.Recent development in aluminium alloys for aerospace applications[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,20001(1):102-107. |
| [3] | Han, N.;Zhang, X.;Liu, S.;Ke, B.;Xin, X..Effects of pre-stretching and ageing on the strength and fracture toughness of aluminum alloy 7050[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,201110/11(10/11):3714-3721. |
| [4] | 宋丰轩;张新明;刘胜胆;韩念梅;花隆.时效对7050铝合金预拉伸板抗腐蚀性能的影响[J].中国有色金属学报,2013(3):645-651. |
| [5] | 韩念梅;张新明;刘胜胆;黄乐瑜;辛星;何道广.回归再时效对7050铝合金强度和断裂韧性的影响[J].中国有色金属学报,2012(7):1871-1882. |
| [6] | 冯迪;张新明;邓运来;刘胜胆;吴泽政;郭奕文.预时效温度及回归加热速率对7055铝合金组织及性能的影响[J].中国有色金属学报,2014(5):1141-1150. |
| [7] | 曾世宝;叶凌英;刘胜胆;邬沛卿;单朝军;邓运来;张新明.均匀化升温速率对7N01铝合金组织与力学性能的影响[J].中国有色金属学报,2014(9):2228-2234. |
| [8] | 张建波;张永安;何振波;金龙兵;朱宝宏;李志辉.自然时效对7N01铝合金组织和性能的影响[J].稀有金属,2012(2):191-195. |
| [9] | 宋涛;高家诚;乔丽英;高安江.7N01铝合金120℃单级时效的组织和性能[J].材料热处理学报,2011(7):104-109. |
| [10] | 付高;邓运来;王亚风;戴青松;张新明.微量元素含量对Al-Zn-Mg合金组织与性能的影响[J].中国有色金属学报,2015(10):2632-2641. |
| [11] | 吴翼贻;黄清添;林昆民.AA7005铝合金抗应力腐蚀制程之研究[J].金属热处理,2005(z1):8-12. |
| [12] | 邬沛卿 .热处理制度对7N01铝合金性能的影响[D].中南大学,2014. |
| [13] | M.M. Sharma;M.F. Amateau;T.J. Eden.Hardening mechanisms of spray formed Al-Zn-Mg-Cu alloys with scandium and other elemental additions[J].Journal of Alloys and Compounds: An Interdisciplinary Journal of Materials Science and Solid-state Chemistry and Physics,20061/2(1/2):135-142. |
| [14] | G. Waterloo;V. Hansen;J. Gjonnes;S. R. Skjervold.Effect of predeformation and preaging at room temperature in Ai-Zn-Mg-(Cu,Zr)alloys[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,20011/2(1/2):226-233. |
| [15] | K. Stiller;P.J. Wdrren.Investigation of precipitation in an Al-Zn-Mg alloy after two-step ageing treatment at 100°and 150℃[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,19991(1):55-63. |
| [16] | 刘继华;李荻;朱国伟;刘培英.7075铝合金应力腐蚀敏感性的SSRT和电化学测试研究[J].腐蚀与防护,2005(1):6-9. |
| [17] | 陈小明;宋仁国.7000系铝合金应力腐蚀开裂的研究进展[J].腐蚀科学与防护技术,2010(2):120-123. |
| [18] | S.P.Ringer;K.Hono.Microstructural evolution and age hardening in aluminium alloys: atom probe field-ion microscopy and transmission electron microscopy studies[J].Materials Characterization,20001/2(1/2):101-131. |
| [19] | 苏景新;张昭;曹发和;张鉴清;曹楚南.铝合金的晶间腐蚀与剥蚀[J].中国腐蚀与防护学报,2005(3):187-192. |
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