摘要
采用拉伸试验、电导率测试及透射电镜观察等方法 ,研究了重固溶温度和过时效处理时间对70 5 5铝合金组织与性能的影响。结果表明 ,12 0℃× 3h +180℃× 8h过时效处理后 ,经过不同温度(4 4 0℃～ 4 90℃ )重新固溶处理以及 12 0℃ 2 4h再时效后 ,70 5 5铝合金的电导率随重固溶温度的上升而降低 ,但强度升高 ;延长过时效时间 (12 0℃× 3h +180℃× 4h～ 2 0h) ,4 70℃× 1h重固溶处理后 ,合金电导率略微上升 ,而强度逐渐降低。组织观察表明 ,过时效处理形成的粗大析出相在不同温度重固溶时的重新溶解程度不同 ,重固溶温度越低 ,粗大析出相溶解越不充分 ,从而形成与回归再时效处理相类似的组织结构 ;同时 ,过时效及重固溶处理也有利于Fe、Si和Zr等残留固溶原子以化合物的形式充分析出 ,因此利用该工艺可以在保持强度不降低的前提下 ,提高合金的电导率 ,并最终提高合金的抗应力腐蚀性能。
The effects of re-solution temperature and over-ageing time on microstructures and mechanical properties of 7055 aluminum alloy were investigated by tensile test, electrical conductivity measurement and TEM observation. The experimental results show that the electrical conductivity of the over-aged alloy in 120℃×3h+180℃×8h temper decreased with increase of re-solution temperature after re-solution in the range of 440℃～490℃×1h and 120℃×24h re-ageing, but the strength lowered correspondingly. Prolonging over-ageing time from 180℃×4h to 20h slightly increased the electrical conductivity of the alloy re-solutioned at 470℃ for 1h and decreased its strength. TEM observations revealed that the coarse precipitates formed during over-ageing did not dissolve fully, which provided the alloy with microstructures and properties similar to retrogression and reageing(RRA) treatment.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2004年第3期57-61,共5页
Transactions of Materials and Heat Treatment
基金
国家 973重点基础研究项目 (G1 9990 6490 0 9)
