(中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點(diǎn)實(shí)驗(yàn)室， 長(zhǎng)沙 410083)
摘 要: 通過時(shí)效曲線測(cè)定和慢應(yīng)變拉伸實(shí)驗(yàn)以及透射電鏡觀察，研究了不同熱處理制度對(duì)一種7055型鋁合金拉伸性能、時(shí)效組織和抗應(yīng)力腐蝕性能的影響。結(jié)果表明，實(shí)驗(yàn)合金采用RRA處理，可使晶內(nèi)保持類似于T6狀態(tài)的顯微結(jié)構(gòu)，同時(shí)使晶界析出物的大小和分布特征與過時(shí)效狀態(tài)相當(dāng)，從而可使強(qiáng)度達(dá)到T6峰值狀態(tài)的水平，抗應(yīng)力腐蝕性能則優(yōu)于T6狀態(tài)。 RRA處理改善抗應(yīng)力腐蝕性能的原因可能與粗大、孤立分布的晶界析出物有助于阻止氫脆以及縮小界內(nèi)和晶界電化學(xué)差異有關(guān)。
關(guān)鍵字: RRA處理； 應(yīng)力腐蝕； 顯微組織； 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
