(1. 北京有色金屬研究總院 國家有色金屬及電子材料分析測試中心，北京 100088；
2. 北京航空航天大學(xué) 材料科學(xué)與工程學(xué)院，北京 100191)
摘 要: 采用光學(xué)顯微鏡和掃描電鏡等研究新型含鈧2124鋁合金兩種不同取向試樣在3.5%NaCl(質(zhì)量分?jǐn)?shù))溶液中的應(yīng)力腐蝕開裂行為，并對裂紋尖端形貌和腐蝕形貌進(jìn)行分析。結(jié)果表明：該鋁合金在應(yīng)力腐蝕時首先發(fā)生陽極溶解，裂紋尖端晶界處大量聚集的腐蝕產(chǎn)物產(chǎn)生的楔入力和外加應(yīng)力的共同作用促使預(yù)制裂紋在腐蝕介質(zhì)中進(jìn)一步沿晶界向縱深方向擴(kuò)展；兩種取向試樣在全浸腐蝕時均發(fā)生明顯的晶間腐蝕，容易發(fā)生應(yīng)力腐蝕開裂；得到了不同取向試樣的應(yīng)力腐蝕裂紋擴(kuò)展規(guī)律及應(yīng)力腐蝕強(qiáng)度因子門檻值，并探討取向?qū)?yīng)力腐蝕開裂行為的影響。
關(guān)鍵字: 含鈧2124鋁合金；取樣方向；楔入力；應(yīng)力腐蝕開裂
（1. National Center of Analysis and Testing for Non-ferrous Metals & Electronic Materials,
General Research Institute for Nonferrous Metals, Beijing 100088, China;
2. School of Materials Science and Engineering, Beihang University, Beijing 100191, China）
Abstract:The stress corrosion cracking behavior of the novel 2124 aluminum alloy containing Sc with different sampling orientations in 3.5%NaCl (mass fraction) solution was studied by optical microscopy and scanning electron microscopy. Furthermore, the morphologies at the crack tip before and after corrosion were analyzed. The results show that the anodic dissolution occurs first during the stress corrosion, and the cooperation of the wedging action incured by the mass of corrosion products gathering at the grain boundaries and the applied stress drives the pre-cracks extending along the grain boundaries to the depth direction further in the corrosive medium. Obvious intergranular corrosion of the samples of the two orientations occurs under the total immersion corrosion and stress corrosion cracking takes places easily. The stress corrosion crack propagation law and the stress corrosion intensity factor threshold of the samples of different orientations are obtained. The effect of the sampling orientation on the stress corrosion cracking behavior was investigated.
Key words: 2124 aluminum alloy containing Sc; sampling orientation; wedged action; stress corrosion cracking
