(中南大学 有色金属材料科学与工程教育部重点实验室， 长沙 410083)
摘 要: 通过时效曲线测定和慢应变拉伸实验以及透射电镜观察，研究了不同热处理制度对一种7055型铝合金拉伸性能、时效组织和抗应力腐蚀性能的影响。结果表明，实验合金采用RRA处理，可使晶内保持类似于T6状态的显微结构，同时使晶界析出物的大小和分布特征与过时效状态相当，从而可使强度达到T6峰值状态的水平，抗应力腐蚀性能则优于T6状态。 RRA处理改善抗应力腐蚀性能的原因可能与粗大、孤立分布的晶界析出物有助于阻止氢脆以及缩小界内和晶界电化学差异有关。
关键字: RRA处理； 应力腐蚀； 显微组织； 7055合金
a 7055 type aluminum alloy
（The Key Laboratory of Nonferrous Metal Materials Science and
Engineering of Ministry of Education，Central South University，
Changsha 410083, P.R.China）
Abstract:The influence of heat treatment on the tensile properties， microstructure and resistance to SCC of a 7055 type aluminum alloy was investigated using aging curves measurement， slow strain tensile test and TEM observations. The results show that RRA treatment can provide the microstructure of a T6 temper in the matrix and the grain boundary precipitate structure possessed of a overaged(T7) condition. Thus strength of the alloy can be achieved the levels of T6 temper and the resistance to SCC better than that of T6 temper. Improved resistance to SCC by the RRA treatment is believed to result from the large coarsening grain boundary precipitates， which form during RRA treatment and can inhibite hydrogen embrittlement and decrease the electrochemical difference between grain boundaries and grain interior.
Key words: RRA treatment； stress corrosion； microstructure； 7055 alloy
