(1. 中南大學(xué) 輕合金研究院，長(zhǎng)沙 410083；
2. 中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083；
3. 中南大學(xué) 有色金屬先進(jìn)結(jié)構(gòu)材料與制造協(xié)同創(chuàng)新中心，長(zhǎng)沙 410083)
摘 要: 采用金相、掃描電鏡(SEM)觀察、力學(xué)拉伸實(shí)驗(yàn)、剝落腐蝕實(shí)驗(yàn)、電化學(xué)腐蝕實(shí)驗(yàn)以及慢應(yīng)變速率拉伸實(shí)驗(yàn)等分析測(cè)試方法研究稀土Ce對(duì)7A52鋁合金組織與性能的影響。研究表明:稀土Ce降低合金的強(qiáng)度，隨著Ce含量從0增加至0.6%(質(zhì)量分?jǐn)?shù))，合金的抗拉強(qiáng)度由494.81 MPa降低至476.46 MPa，屈服強(qiáng)度由454.24 MPa降低至435.84 MPa，伸長(zhǎng)率由10.15%降低至7.06%；稀土Ce導(dǎo)致合金的耐腐蝕性能得到大幅提高，耐腐蝕性能由大到小的順序?yàn)?0.5%Ce、0.6%Ce、0.25%Ce、0Ce。其原因是，添加稀土Ce的合金中會(huì)形成一種大塊多邊形狀的脆性稀土相(AlxMgyZnz(TiCr)mCe)，該脆性稀土相容易成為拉伸斷裂的裂紋源，降低7A52鋁合金的強(qiáng)度。同時(shí)，稀土Ce能提高合金表層氧化膜腐蝕時(shí)的電荷轉(zhuǎn)移電阻(Rt)，使其耐腐蝕性能得到提高。
關(guān)鍵字: 7A52鋁合金；Ce；應(yīng)力腐蝕；力學(xué)性能
（1. Light Alloy Research Institute, Central South University, Changsha 410083, China;
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
3. Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center,
Central South University, Changsha 410083, China）
Abstract:The effects of RE Ce on the microstructure and properties of 7A52 aluminum alloy were studied by optical microstructure, scanning electron microscopy(SEM), mechanical tensile testing, exfoliation corrosion testing, electrochemical corrosion testing and slow strain rate tensile testing. The results show that the tensile strength decreases from 494.81 MPa to 476.46 MPa, the yield strength decreases from 454.24 MPa to 435.84 MPa and the elongation decreases from 10.15% to 7.06% when Ce content increases from 0 to 0.6% (mass fraction). The corrosion resistance of 7A52 alloy is greatly improved by Ce addition, with descending order as follows: 0.5%, 0.6%, 0.25%, 0. It is attributed to that by Ce addition, a brittle polygonal shape RE-rich-phase (AlxMgyZnz(TiCr)mCe) forms in the alloy, which becomes the crack source in the tensile test, leading to the decrease of the strength of 7A52 alloy. Moreover, the charge transfer resistance of the oxide film on the surface is enhanced by Ce addition, and thus the corrosion resistance is improved.
Key words: 7A52 aluminum alloy; Ce; stress corrosion; mechanical property
