Poor corrosion resistance is a critical barrier to the widespread application of magnesium alloys. Statistically, the literature reported that approximately 70 % of as-cast AZ31 magnesium alloys exhibit corrosion rates exceeding 1 mm ·y⁻¹ in 3.5 wt.% NaCl solution, which is unacceptable for industrial use. Furthermore, there is a considerable discrepancy in the corrosion rates reported by different studies (as-cast alloys ranging from 0.4 to 215 mm ·y⁻¹). These phenomena may be attributed to the uncontrollable content of impurity elements in commercial magnesium alloys, which fluctuate widely between batches. In the present work, we prepared as-cast AZ31 magnesium alloys with different impurity contents using two different purities of raw magnesium (Mg-99.9% and Mg-99.99%). The impact of impurity contents on the corrosion resistance of AZ31 magnesium alloys was then analyzed. The AZ31 magnesium alloy prepared with 99.99% raw magnesium showed superior corrosion resistance compared with that prepared with 99.9% raw magnesium, with a reduction in corrosion rate by approximately 98 % and a decrease in the fluctuation range of corrosion rate by 91 %. Thus, enhancing the purity of raw magnesium is an effective method to improve both the corrosion resistance and consistency of magnesium alloys.

中文翻译：

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通过使用高纯度镁原料增强 AZ31 镁合金的耐腐蚀性


耐腐蚀性差是镁合金广泛应用的关键障碍。据统计，文献报道了大约 70% 的铸态 AZ31 镁合金的腐蚀速率超过 1 mm ·y⁻¹ 在 3.5 wt.% 的 NaCl 溶液中，这对于工业用途来说是不可接受的。此外，不同研究报告的腐蚀速率存在相当大的差异（铸态合金从 0.4 到 215 毫米 ·y⁻¹） 的这些现象可能归因于商业镁合金中杂质元素的含量不可控，这些杂质元素在批次之间波动很大。在本工作中，我们使用两种不同纯度的镁原料 （Mg-99.9% 和 Mg-99.99%） 制备了具有不同杂质含量的铸态 AZ31 镁合金。然后分析了杂质含量对 AZ31 镁合金耐腐蚀性的影响。与99.9%镁原料制备的AZ31镁合金相比，99.99%的镁原料制备的AZ31镁合金表现出优异的耐腐蚀性，腐蚀速率降低了约98 %，腐蚀速率的波动范围降低了91 %。因此，提高原镁的纯度是提高镁合金的耐腐蚀性和一致性的有效方法。