Al-xMg-3.1Zn铝合金的应力腐蚀开裂行为及其机制

The stress corrosion cracking behavior of Al-xMg-3.1Zn aluminum alloys

摘要:

本文通过慢应变速率拉伸实验和动态电解充氢实验分别研究了Al-xMg-3.1Zn铝合金的应力腐蚀开裂行为及其氢脆行为。结合宏观断口和微观断口形貌分析研究了合金发生应力腐蚀开裂的进程。通过对合金应力腐蚀开裂的机制进行分析阐明了合金中Mg元素含量对合金应力腐蚀开裂行为的影响。研究结果表明在该合金体系中存在应力腐蚀开裂，且合金的应力腐蚀敏感性随合金中Mg含量的降低而降低；这与合金的阳极溶解行为与氢脆行为随Mg元素含量降低而减弱有着直接的关系。在这当中，合金中晶界析出相的数量随Mg元素含量降低而减少起到了至关重要的作用。

Abstract:

The stress corrosion cracking and hydrogen embrittlement of the Al-xMg-3.1Zn aluminum alloys were studied by slow strain rate tensile tests and dynamic electrolytic hydrogen charging experiments, respectively. The effect of Mg on the stress corrosion cracking behaviors was indicated combining with transmission electron microscopy and fracture analysis. The results showed that the stress corrosion cracking was happened in the studied alloys, and the corrosion susceptibility decreased with a decrease of Mg content due to the decrease of the grain boundary precipitates continuity. This was result from the decrease in the anodic dissolution of grain boundary precipitates and hydrogen embrittlement behaviors with a decrease of Mg content.