第12期 李志辉等:低温回归再时效对7B04一T651铝合金厚板组织与性能的影响 .1387. 性与T7状态较为相似:晶界析出物粗大呈完全不 [2]Xiong B Q.Zhang Y A.Shi L K.High property aluminum alloys 连续分布,沿晶界有较宽的P℉Z存在,宽度约为 prepared by spray forming process.Mater Rev.2000.14(12):50 (熊柏青,张永安,石力开.喷射成形技术制备高性能铝合金 30~50nm左右,由此可见,RRA处理后的组织综 材料.材料导报,2000,14(12):50) 合了T6与T7处理的优点,对抗应力腐蚀性能是极 [3]Zhang Y A,Xiong B Q.Shi L K.Research status of rapidly so- 其有利的(电导率的测试结果也证实了这一点),并 lidified ultra-high strength aluminum alloys.Mater Rev,2005. 且还能够保持很高的强度,从理论上来说,基本达到 19(10):91 了RRA处理的目的, (张永安,熊柏青,石力开,快速凝固7000系超高强铝合金的 研究现状.材料导报,2005.19(10):91) 3结论 [4]Wang T,Yin Z M.Research status and development trend of ul- trahigh strength aluminum alloys.Chin J Rare Met.2006.30 (1)回归温度和时间对合金最终的性能影响较 (2):197 大,采用合理的回归处理工艺可使合金保持较高强 (王涛,尹志民·高强变形铝合金的研究现状和发展趋势,稀 度的同时,电导率明显提高,合金分别在170,180 有金属,2006,30(2):197) 与190℃回归再时效处理,要使合金的电导率超过 [5]Heinz A.Haszler A,Keidel C,et al.Recent development in alu- 21.0MSm-1(相当于T74状态的电导率),回归时 minium alloys for aerospace applications.Mater Sci Eng.2000. A280:102. 间分别需要120,60和40min,此时合金抗拉强度 [6]Park JK.Influence of retrogression and reaging treatments on the 可保持在570~580MPa左右,与峰时效强度相比下 strength and stress corrosion resistance of aluminium alloy 7075- 降了约2%~3%. T6.Mater Sci Eng.1988.A103:223 (2)回归过程中,回归初期晶内的GP区及细 [7]Cina B,Ranish B.New Technology for Reducing Susceptibility 小的相溶解导致合金的强度下降,随后T相的重 to Stress Corrosion of High Strength Aluminium Alloys:US Patent,3856584.1974-12-24 新析出又使得合金的强度有所回升,继续延长回归 [8]Tanaka M.Henon C.Warner T.Microstructural evolution of a 时间,T相的熟化及”相的不断析出会使得合金强 new aerospace 7XXX alloy during retrogression and re-ageing 度逐渐下降,回归后进行再时效处理,可相的再析 treatment.Mater Sei Forum,2006,519/521:345 出是合金的强度和电导率提高的主要原因, [9]Denzer D K,Chakrabarti D J,Liu J.et al.Method for Increas- (③)RRA态合金的晶内组织与T6状态相似, ing the Strength and/or Corrosion Resistance of 7000 Series Al Aerospace Alloy Products:US Patent,2003/0051784 A1.2003- 析出相细小呈弥散分布;而晶界组织与双级T7时 03-20 效组织特征相似,晶界析出相粗大呈不连续分布,晶 [10]Ferrer C P,Koul M G.Connolly B J,et al.Improvements in 界两侧伴之以明显的晶界无析出带. strength and stress corrosion cracking properties in aluminum al- loy 7075 via low temperature retrogression and reageing heat 参考文献 treatments.Corrosion.2003.59(6):520 [1]Fridlyander I N,Dobromyslov A V,Tkachenko E A,et al.Ad- [11]Lumley R N.Polmear I J.Morton A J.Development of proper- vanced high"strength aluminum-base materials.Met Sci Heat ties during secondary ageing of aluminium alloys.Mater Sci Fo- Trea,2005,47(7/8):269 rum,2003,426/427:303性与 T7状态较为相似:晶界析出物粗大呈完全不 连续分布沿晶界有较宽的 PFZ 存在宽度约为 30~50nm 左右.由此可见RRA 处理后的组织综 合了 T6与 T7处理的优点对抗应力腐蚀性能是极 其有利的(电导率的测试结果也证实了这一点)并 且还能够保持很高的强度从理论上来说基本达到 了 RRA 处理的目的. 3 结论 (1) 回归温度和时间对合金最终的性能影响较 大采用合理的回归处理工艺可使合金保持较高强 度的同时电导率明显提高.合金分别在170180 与190℃回归再时效处理要使合金的电导率超过 21∙0MS·m -1(相当于 T74状态的电导率)回归时 间分别需要12060和40min此时合金抗拉强度 可保持在570~580MPa 左右与峰时效强度相比下 降了约2%~3%. (2) 回归过程中回归初期晶内的 GP 区及细 小的η′相溶解导致合金的强度下降随后η′相的重 新析出又使得合金的强度有所回升继续延长回归 时间η′相的熟化及η相的不断析出会使得合金强 度逐渐下降.回归后进行再时效处理η′相的再析 出是合金的强度和电导率提高的主要原因. (3) RRA 态合金的晶内组织与 T6状态相似 析出相细小呈弥散分布;而晶界组织与双级 T7时 效组织特征相似晶界析出相粗大呈不连续分布晶 界两侧伴之以明显的晶界无析出带. 参 考 文 献 [1] Fridlyander I NDobromyslov A VTkachenko E Aet al.Advanced high-strength aluminum-base materials. Met Sci Heat T reat200547(7/8):269 [2] Xiong B QZhang Y AShi L K.High-property aluminum alloys prepared by spray-forming process.Mater Rev200014(12):50 (熊柏青张永安石力开.喷射成形技术制备高性能铝合金 材料.材料导报200014(12):50) [3] Zhang Y AXiong B QShi L K.Research status of rapidly solidified ultra-high strength aluminum alloys. Mater Rev2005 19(10):91 (张永安熊柏青石力开.快速凝固7000系超高强铝合金的 研究现状.材料导报200519(10):91) [4] Wang TYin Z M.Research status and development trend of ultra-high strength aluminum alloys.Chin J Rare Met200630 (2):197 (王涛尹志民.高强变形铝合金的研究现状和发展趋势.稀 有金属200630(2):197) [5] Heinz AHaszler AKeidel Cet al.Recent development in aluminium alloys for aerospace applications.Mater Sci Eng2000 A280:102. [6] Park J K.Influence of retrogression and reaging treatments on the strength and stress corrosion resistance of aluminium alloy 7075- T6.Mater Sci Eng1988A103:223 [7] Cina BRanish B.New Technology for Reducing Susceptibility to Stress Corrosion of High Strength Aluminium Alloys:US Patent3856584.1974-12-24 [8] Tanaka MHénon CWarner T.Microstructural evolution of a new aerospace 7XXX alloy during retrogression and re-ageing treatment.Mater Sci Forum2006519/521:345 [9] Denzer D KChakrabarti D JLiu Jet al.Method for Increasing the Strength and/or Corrosion Resistance of 7000 Series Al Aerospace Alloy Products:US Patent2003/0051784A1.2003- 03-20 [10] Ferrer C PKoul M GConnolly B Jet al.Improvements in strength and stress corrosion cracking properties in aluminum alloy 7075 via low-temperature retrogression and re-ageing heat treatments.Corrosion200359(6):520 [11] Lumley R NPolmear I JMorton A J.Development of properties during secondary ageing of aluminium alloys.Mater Sci Forum2003426/427:303 第12期 李志辉等: 低温回归再时效对7B04-T651铝合金厚板组织与性能的影响 ·1387·