(1. 合肥工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，合肥 230009；
2. 合肥工業(yè)大學(xué) 智能制造技術(shù)研究院，合肥 230009)
摘 要: 采用等徑角擠壓(ECAP)和固溶時效處理獲得超高強(qiáng)鋁合金，并采用透射電子顯微鏡、掃描電鏡以及電化學(xué)工作站等測試手段對其微觀結(jié)構(gòu)演變以及電化學(xué)腐蝕行為進(jìn)行研究。結(jié)果表明：等徑角擠壓變形后晶粒細(xì)化至亞微米(9.68→1 μm)，大變形誘導(dǎo)的溶質(zhì)原子偏析和不連續(xù)脫溶效應(yīng)造成第二相長大(53→416 nm)和晶界偏聚；大塑性變形材料經(jīng)固溶時效處理后，部分第二相的晶界偏析現(xiàn)象減弱，呈細(xì)小顆粒狀彌散分布于鋁基體中。細(xì)晶組織和高能缺陷有利于形成附著力良好且致密穩(wěn)定的氧化膜，晶界偏析的減弱和彌散細(xì)小的第二相抑制了點蝕對晶間腐蝕的促進(jìn)作用，最終顯著優(yōu)化超高強(qiáng)鋁合金的耐腐蝕性能。
關(guān)鍵字: 超高強(qiáng)鋁合金；等徑角擠壓；高能缺陷；第二相；腐蝕行為
（1. School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China;
2. Intelligent Manufacturing Institute, Hefei University of Technology, Hefei 230009, China）
Abstract:Ultrahigh strength aluminum alloys were prepared by equal channel angular pressing (ECAP) and solution aging treatment. The microstructure evolution and electrochemical corrosion behavior of the alloy were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and electrochemical workstation. The results show that grains are refined to submicron level after ECAP. Solute segregation and discontinuous dissolution caused by severe plastic deformation lead to the coarsening of secondary phases particles and segregation at grain boundary. Partial secondary phase particles in Al-Zn-Mg-Cu alloy are refined and dispersed in aluminum matrix after the process of severe plastic deformation and solution aging, which demonstrates the decrease of secondary phase segregation at grain boundary. The dense and stable oxide films, as well as the fine secondary phase particles with diffused distribution, have beneficial influence on the improvement of corrosion resistance of ultra-high strength aluminum alloy. The dense and stable oxide films with high adhesion are formed by fine grain structure and high energy defects. Intergranular corrosion is depressed by dispersed fine secondary phase and decrease of grain boundary segregation.
Key words: ultra high strength aluminum alloy; equal channel angular pressing; high energy defect; secondary phase; corrosion behavior
