The strength of traditional Al-Mg alloys primarily depends on cold deformation and increasing Mg content, but it can become susceptible to stress corrosion cracking (SCC) when the Mg content is high (>3 wt.%). Simultaneous optimizing strength and SCC resistance in Al-Mg alloys is challenging. This study introduces a nanostructured Al-10Mg (10 wt.%) alloy with improved strength and SCC resistance by dynamic plastic deformation and optimized annealing. The as-deformed sample exhibits a nano-scaled lamellar structure. With rising annealing temperatures, structure size of the alloy increases while dislocation density decreases, transitioning lamellar to equiaxed grains. Nanostructured Al-10Mg alloys annealed at 250°C exhibit superior mechanical properties and reduced SCC susceptibility at sensitization state. The high fraction of low-angle grain boundaries with a reduction in dislocation density can effectively suppress the nucleation and growth of grain boundary precipitates (GBPs) during sensitization, thereby maintaining a relatively low GBPs coverage. The results provide guidance for designing Al-Mg alloys that are stronger and more resistant to SCC with higher Mg content.

中文翻译：

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通过纳米结构和受控退火提高高 Mg Al-Mg 合金的强度和抗应力腐蚀开裂性


传统 Al-Mg 合金的强度主要取决于冷变形和增加的 Mg 含量，但当 Mg 含量高 （>3 wt.%） 时，它很容易发生应力腐蚀开裂 （SCC）。同时优化 Al-Mg 合金的强度和抗 SCC 性具有挑战性。本研究介绍了一种纳米结构的 Al-10Mg （10 wt.%） 合金，该合金通过动态塑性变形和优化退火提高了强度和抗 SCC 性。变形后的样品表现出纳米级的层状结构。随着退火温度的升高，合金的结构尺寸增加，而位错密度降低，将层状晶粒转变为等轴晶粒。在 250°C 下退火的纳米结构 Al-10Mg 合金表现出优异的机械性能，并且在敏化状态下降低了 SCC 敏感性。高比例的低角度晶界伴位错密度的降低可以有效抑制敏化过程中晶界沉淀物 （GBPs） 的成核和生长，从而保持相对较低的 GBPs 覆盖率。结果为设计更坚固、更耐 Mg 含量较高时 SCC 的 Al-Mg 合金提供了指导。