热处理后Zr-4合金高温氧化行为研究

High-Temperature Oxidation Behavior of Heat Treated Zr-4 Alloy

为了了解马氏体态Zr-4合金的高温氧化性能,以热处理后马氏体态的Zr-4合金为研究对象,利用热分析天平,采用动态连续称重法对Zr-4合金分别在450℃水蒸气、500℃水蒸气和500℃空气条件下进行氧化试验,对其氧化动力学规律进行了分析,利用扫描电子显微镜和能谱分析仪对氧化层的形貌和成分进行了观察分析.试验结果表明:Zr-4合金在450℃水蒸汽、500℃的水蒸气和500℃空气条件下的氧化动力学符合抛物线规律y=a+btc,随着氧化时间的延长,氧化速度减慢;氧化温度升高,氧化速度增快.在氧化220h后会形成厚度均匀的氧化膜,厚度分别为10.8μm、35μm和47.7μm;氧化膜表面有部分破裂和脱落;氧化膜主要含Zr和O元素,从氧化膜外表面到基体,O元素含量逐渐降低,Zr元素含量逐渐增加.

In order to understand high-temperature oxidation behavior of martensitic Zr-4 alloy, the oxidation dynamic rules of Zr-4 alloys at 450 ℃ vapor, 500 ℃ vapor and 500 ℃ air were analyzed by dynamic continuous weighing methods. The microstructures and compositions of the oxide layers were observed by SEM and EDS. The results showed. Oxidation dynamics of Zr-4 alloys at 450 ℃ vapor, 500 ℃ vapor and 500 ℃ air conditions were in line with parabolic rules. The oxidation speeds decreased with the extension of oxidation time,and the oxidation rates increased with increasing temperature. After Zr-4 alloy oxidized at 450 ℃ vapor,500 ℃ vapor and 500 ℃ air conditions for 220 h,the oxide layer thickness were respectively 10.8 μm,35 μm and 47.7 μm,and oxidation layers became broken and peeling off. Zr and O contents in the layers individually increased and decreased with distance from surface to substrate.