回归再时效中预时效温度对7050铝合金应力腐蚀性能的影响

采用硬度测试、电导率测试、慢应变速率拉伸、透射电镜和扫描电镜等方法,研究了回归再时效热处理工艺中预时效温度对7050铝合金微观组织和应力腐蚀性能的影响。结果表明：随着预时效温度升高,回归再时效后7050铝合金晶内析出相从以GP区为主转变为以η′相为主,晶界析出相逐渐粗化,晶界变得不连续分布,合金应力腐蚀敏感性降低;但晶界无沉淀析出带宽度增加,120℃时达到140nm,易导致应力集中和阳极溶解,合金抗应力腐蚀性能下降。预时效温度为80℃,即稍微欠时效时,7050铝合金抗应力腐蚀性能较好,在缓慢应变速率（10-6s-1）和3.5%NaCl溶液腐蚀介质下,合金抗拉强度为473.5MPa,伸长率为10...

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Bibliographic Details
Published in材料工程 no. 5; pp. 29 - 34
Main Author 辛星 张新明 刘胜胆 宋丰轩 陈彬
Format Journal Article
LanguageChinese
Published 中南大学材料科学与工程学院,长沙,410083 2014
Subjects
7050铝合金
应力腐蚀
析出相
预时效温度
析出相
应力腐蚀
7050 aluminum alloy
stress corrosion
precipitated phase
预时效温度
7050铝合金
pre-aging temperature
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ISSN1001-4381
1001-4381
DOI10.11868/j.issn.1001-4381.2014.05.006

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Summary:采用硬度测试、电导率测试、慢应变速率拉伸、透射电镜和扫描电镜等方法,研究了回归再时效热处理工艺中预时效温度对7050铝合金微观组织和应力腐蚀性能的影响。结果表明：随着预时效温度升高,回归再时效后7050铝合金晶内析出相从以GP区为主转变为以η′相为主,晶界析出相逐渐粗化,晶界变得不连续分布,合金应力腐蚀敏感性降低;但晶界无沉淀析出带宽度增加,120℃时达到140nm,易导致应力集中和阳极溶解,合金抗应力腐蚀性能下降。预时效温度为80℃,即稍微欠时效时,7050铝合金抗应力腐蚀性能较好,在缓慢应变速率（10-6s-1）和3.5%NaCl溶液腐蚀介质下,合金抗拉强度为473.5MPa,伸长率为10.67%,应力腐蚀指数为0.05824。
Bibliography:11-1800/TB
XIN Xing, ZHANG Xin-ming, LIU Sheng-dan, SONG Feng-xuan,CHEN Bin （School of Materials Science and Engineering, Central South University, Changsha 410083, China）
The effect of the pre-aging temperature in retrogression and re-aging （RRA） treatment on stress corrosion resistance of 7050 aluminum alloy was investigated by means of hardness tests, conductivity tests, slow strain rate tensile （SSRT） tests, transmission electron microscopy （TEM） and scanning electron microscopy （SEM）. The results show that when the pre-aging temperature increases, the main intragranular precipitates in 7050 aluminum alloy transform from GP zones to 7/1 phases after RRA. The grain boundary precipitates become coarser and consequently the grain boundary becomes discontinuous, which leads to the reduction of sensitivity of stress corrosion. At the meantime, the precipitate free zone （PFZ） becomes wider, whose width goes up to 140nm when pre-aging tem- perature rises to 120~C, causing stress concentration and anode dissolution
ISSN:1001-4381
1001-4381
DOI:10.11868/j.issn.1001-4381.2014.05.006