赵信毅,张海洋,肖遥,等.Mg-9Al-xCa合金高温氧化行为研究[J].精密成形工程,2025,17(1):9-16.
ZHAO Xinyi,ZHANG Haiyang,XIAO Yao,et al.High Temperature Oxidation Behavior of Mg-9Al-xCa Alloys[J].Journal of Netshape Forming Engineering,2025,17(1):9-16. |
| Mg-9Al-xCa合金高温氧化行为研究 |
| High Temperature Oxidation Behavior of Mg-9Al-xCa Alloys |
| 投稿时间：2024-05-20 |
| DOI：10.3969/j.issn.1674-6457.2025.01.002 |
| 中文关键词: 镁合金 高温氧化 Ca含量 铸态组织 热力学 |
| 英文关键词: magnesium alloy high-temperature oxidation Ca content as-cast structure thermodynamics |
| 基金项目:国家自然科学基金(52105349) |
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| 摘要点击次数: 47 |
| 全文下载次数: 5 |
| 中文摘要: |
| 目的 研究高温下Ca含量对镁合金等温氧化行为的影响，分析Ca元素在氧化过程中的作用机理，为镁合金在高温下的应用提供参考。方法 以Mg-9Al-xCa合金体系为对象﹐对铸态合金组织进行分析。同时利用自主设计的实验设备在480 ℃下对不同Ca含量镁合金进行了不同时长的等温氧化实验，对氧化增重进行了测量，对合金氧化层进行了表征分析，并利用热力学计算揭示了作用机理。结果 Mg-9Al合金中主要相组成为基体α-Mg相以及晶界处的Mg17Al12相。当添加Ca元素后，合金主要由α-Mg、晶界处的Mg17Al12相和Al2Ca相组成，其中Al2Ca相与α-Mg形成(α+Al2Ca)共晶。随着Ca含量的增加，合金熔体凝固时生成的Mg17Al12相逐渐减少，组织中(α+Al2Ca)共晶比例不断提高。在氧化200 min后，Mg-9Al合金氧化增重达到32.781 mg/cm2，氧化层形貌形成凸起和凹陷结构，含Ca镁合金氧化增重大幅度降低，Mg-9Al-5.0Ca氧化增重仅为0.046 mg/cm2，不同Ca含量镁合金氧化层形貌表现出差异性。由热力学计算得知，在Ca含量大于0.4%(质量分数)情况下，Ca元素可更容易发生氧化反应生成以CaO为主的氧化层。结论 Ca含量是影响镁合金氧化行为的关键因素，随着Ca含量的增加，镁合金的抗氧化性能逐步提升。 |
| 英文摘要: |
| The work aims tostudy the effect of Ca content on the isothermal oxidation behavior of magnesium alloys at high temperature, and analyze the mechanism of Ca in the oxidation process, so as to provide a reference for the application of magnesium alloys at high temperature. The as-cast alloy structure was analyzed with the Mg-9Al-xCa alloy system as the object. At the same time, isothermal oxidation experiments were carried out for magnesium alloys with different Ca contents at 480 ℃ for different durations using self-designed experimental equipment. The oxidation weight gain was measured, the oxide layer of the alloy was characterized and analyzed, and the mechanism of action was revealed by thermodynamic calculations. The main phases in the Mg-9Al alloy were the matrix α-Mg phase and the Mg17Al12 phase at the grain boundary. When Ca was added, the alloy was mainly composed of α-Mg, Mg17Al12 phase at the grain boundary and Al2Ca phase, in which the Al2Ca phase formed (α+Al2Ca) eutectic with α-Mg. With the increase of Ca content, the Mg17Al12 phase formed when the alloy melt solidified gradually decreased, and the proportion of (α+Al2Ca) eutectic in the microstructure increased. After oxidation for 200 min, the oxidative weight gain of Mg-9Al alloy reached 32.781 mg/cm2, a convex and concave structure formed on the oxide layer, the oxidative weight gain of Mg-9Al-containing magnesium alloy was greatly reduced, and the oxidative weight gain of Mg-9Al-5.0Ca was 0.046 mg/cm2, and the morphology of magnesium oxide layer of magnesium alloy with different Ca content showed differences. Thermodynamic calculations showed that when the Ca content was greater than 0.4wt.%, Ca could easily undergo oxidation reaction to form an oxide layer dominated by CaO. In conclusion, Ca content is the key factor affecting the oxidation behavior of magnesium alloys, and the oxidation resistance of magnesium alloys gradually improves with the increase of Ca content. |
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