微量Zn对Al-4.2Cu-1.4Mg合金应力腐蚀与微观组织的影响

Effect of Trace Zn on Stress Corrosion Resistance and Microstructure of Al-4.2Cu-1.4Mg Alloy

摘要:

通过慢应变速率拉伸、动电位极化曲线测试、透射电子显微分析(TEM)、背散射电子衍射(EBSD)等实验较系统地研究了微量Zn对Al-4.2Cu-1.4Mg合金应力腐蚀与微观组织的影响规律。结果表明，微量Zn的添加显著影响合金的腐蚀性能，且随着Zn含量增加，合金的抗应力腐蚀敏感性以及其对应的开路电位均呈峰值变化，含Zn量0.29%合金的抗腐蚀能力最佳。EBSD研究表明，含0.29%Zn的Al-4.2Cu-1.4Mg合金与其它合金相比存在较多的低能量小角度晶界，这可能是微量Zn显著影响该合金抗应力腐蚀性能的主要原因

Abstract:

The effect of trace addition of Zn on the stress corrosion cracking (SCC) resistance and microstructure of Al-4.2Cu-1.4Mg alloy was studied by means of the slow strain rate technique (SSRT), potentiodynamic polarization test, transmission electron microscopy (TEM) and electron back scattered diffraction (EBSD). The results show that the stress corrosion cracking resistance is improved at the beginning and then decreased with the increase of Zn content. The optimum amount of Zn addition is 0.29% to improve SCC resistance. EBSD results show that there are much more low-angle grain boundaries with low energy in the 0.29% Zn contained alloy, which is probably the main reason why Zn can significantly influence SCC resistance of the alloy