1. School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
2. School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
3. School of Materials Science and Engineering, Central South University, Changsha 410083, China
Abstract：The influence of pre-precipitation on tensile mechanical properties, stress corrosion cracking and intergranular corrosion properties of 2519A aluminium alloy was studied. The mechanism was analyzed through microstructure observation by transmission electron microscope. The results show that for 2519A-T6 samples, pre-precipitation can improve localized corrosion resistance. Stress corrosion cracking time by constant load test increases from 1 day (no pre-precipitation) to 9 days (pre-precipitation). Maximum intergranular corrosion depth decreases from 220μm to 120μm while ultimate tensile strength still remains 400MPa. Localized corrosion properties of 2519A-T8 samples are improved by pre-precipitation. Cracking time prolongs from 10 days (no pre-precipitation) to 14.9 days (pre-precipitation). Maximum intergranular corrosion depth and its corrosion morphology remain unchanged while ultimate tensile strength of pre-precipitation T8-samples is decreased. Proper pre-precipitation can enhance the discontinuity and coarsening of precipitates in grain boundary for both T6 and T8 temper, in which is due to enhancement of localized corrosion resistance.
[1] ZHANG Q H, LI B L, CHEN X, et al. Characteristic microstructure and microstructure evolution in Al-Cu-Mn alloy under projectile impact[J]. Materials Science and Engineering: A, 2012, 531: 12-17.
[2] DYMEK S, DOLLAR M. TEM investigation of age-hardenable Al 2519 alloy subjected to stress corrosion cracking tests[J]. Materials Chemistry and Physics, 2003, 81(2-3): 286-288.
[3] JAMES J F, KRAMER L S, PICKENS J R. Aluminum alloy 2519 in military vehicles[J]. Advance Materials and Processing, 2002, 160(9): 43-46.
[4] KRAMER L S, BLAIR T P, BLOUGH S D, et al. Stress-corrosion cracking susceptibility of various product forms of aluminum alloy 2519[J]. Journal of Materials Engineering and Performance, 2002, 11(6): 645-650.
[5] DAVIES J R. Corrosion of aluminum and aluminum alloys[M]. OH: ASM International Materials Park, 1999.
[6] LI H Z, ZHANG X M, CHEN M A, et al. Effect of pre-deformation on the stress corrosion cracking susceptibility of aluminum alloy 2519[J]. Rare Metals, 2007, 26(4): 385-390.
[7] ZHANG X M, LIU L, YE L, et al. Effect of pre-deformation of rolling combined with stretching on stress corrosion of aluminum alloy 2519A plate[J]. Transactions of Nonferrous Metals Society of China, 2012, 22(1): 8-15.
[8] 张新明, 龚敏如, 李慧中, 等. 2519铝合金薄板在不同时效状态的抗晶间腐蚀能力[J]. 中南大学学报:自然科学版, 2004, 35(3): 349-352.ZHANG X M, GONG M R, LI H Z, et al. Effect of ageing tempers of aluminium alloy 2519 sheet on intergranular corrosion[J]. Journal of Central South University: Science and Technology, 2004, 35(3): 349-352.
[9] 刘瑛, 张新明, 刘波, 等. 预变形量对2519铝合金抗晶间腐蚀性能的影响[J]. 中国有色金属学报, 2006, 16(9): 1545-1550.LIU Y, ZHANG X M, LIU B, et al. Effect of degree of predeformation on corrosion resistance of 2519 aluminum alloy[J]. Transactions of Nonferrous Metals Society of China, 2006, 16(9): 1545-1550.
[10] 李慧中, 张新明, 陈明安, 等. 热处理制度对2519铝合金晶间腐蚀性能的影响[J]. 材料热处理学报, 2005, (1): 20-23. LI H Z, ZHANG X M, CHEN M A, et al. Effect of heat treatment tempers on intergranular corrosion resistance of 2519 aluminum alloy[J].Transactions of Materials and Heat Treatment, 2005, (1): 20-23.
[11] 陈险峰, 林启权, 林高用, 等. 2519铝合金热轧板材晶间腐蚀的研究[J]. 腐蚀科学与防护技术, 2004, (1): 13-16. CHEN X F, LIN Q Q, LIN G Y, et al. Intergranular corrosion of hot rolled plate 2519 aluminium alloy[J]. Corrosion Science and Protection Technology, 2004, (1): 13-16.
[12] HUANG L P, CHEN K H, LI S. Influence of grain-boundary pre-precipitation and corrosion characteristics of inter-granular phases on corrosion behaviors of an Al-Zn-Mg-Cu alloy[J]. Materials Science and Engineering: B, 2012, 177(11): 862-868.
[13] HUANG L P, CHEN K H, LI S, et al. Influence of high-temperature pre-precipitation on local corrosion behaviors of Al-Zn-Mg alloy[J]. Scripta Materialia, 2007, 56(4): 305-308.
[14] 李松. 高温预析出对Al-Zn-Mg系合金强韧化的作用. 长沙: 中南大学, 2003.
[15] 郑强, 陈康华, 黄兰萍, 等. 高温预析出和固溶温度对7A52合金应力腐蚀开裂的影响[J]. 金属热处理, 2005, 30(7): 14-17. ZHENG Q, CHEN K H, HUANG L P, et al. Effect of high temperature pre-precipitation and solution temperature on SCC of 7A52 alloy[J].Heat Treatment of Metals, 2005, 30(7): 14-17.
[16] 陈康华, 刘红卫, 刘允中. 强化固溶对7055铝合金力学性能和断裂行为的影响[J]. 中南工业大学学报:自然科学版, 2000, 31(6): 528-531. CHEN K H, LIU H W, LIU Y Z. The effect of promotively-solutionizing treatment on the mechanical properties and fracture of ultra high strength 7055 aluminum alloys[J]. Journal of Central South University of Technology:Natural Science, 2000, 31(6): 528-531.
[17] 罗勇, 许晓静, 张允康, 等. 强化固溶对含Sr 7085型铝合金晶间腐蚀和剥落腐蚀性能的影响[J]. 航空材料学报, 2012, 32(5): 43-48. LUO Y, XU X J, ZHANG Y K, et al. Effect of enhanced-solid-solution on intergranular corrosion and exfoliation corrosion properties of 7085 type aluminum alloy containing strontium[J]. Journal of Aeronautical Materials, 2012, 32(5): 43-48.
[18] GB7998—87, 铝合金晶间腐蚀测定方法[S].
[19] TAKEDA M, MAEDA Y, YOSHIDA A, et al. Discontinuity of G.P.(I) zone and θ'-phase in an Al-Cu alloy[J]. Scripta Materialia, 1999, 41(6): 643-649.
[20] MULLER I L, GALVELE J R. Pitting potential of high purity binary aluminum alloys-1 Al-Cu alloys. pitting and intergranular corrosion[J]. Corrosion Science, 1977, 13: 179-193.
2014, Vol. 0 
