微量Y对FeCrAl合金包壳力学与氧化性能的影响  

Effect of trace Y on mechanical and oxidation properties of FeCrAl alloy cladding

作　　者：刘洋 马海滨 吴利翔 郭达禧 严俊 杨荣坤 任啟森 薛佳祥 LIU Yang;MA Haibin;WU Lixiang;GUO Daxi;YAN Jun;YANG Rongkun;REN Qisen;XUE Jiaxiang(China Nuclear Power Technology Research Institute,ATF Department,Shenzhen 518000,China;High-safety Accident Tolerant Fuel Technical Engineering Laboratory,Shenzhen 518000,China)

机构地区：[1]中广核研究院有限公司ATF研发专项办公室,深圳518000 [2]核电站高安全性事故溶错燃料技术工程实验室,深圳518000

出　　处：《核技术》2023年第6期15-24,共10页Nuclear Techniques

基　　金：广东省自然科学基金(No.2022A1515010735);广东省联合基金(No.2021M703024)资助。

摘　　要：FeCrAl合金包壳作为事故容错燃料(Accident Tolerant Fuel,ATF)中长期可商用的技术途径得到了广泛关注。本文旨在研究微量Y对FeCrAl合金包壳力学与氧化性能的影响。采用光学显微镜观察FeCrAl和FeCrAlY合金晶粒尺寸和微观形貌。采用爆破试验机和热重分析仪开展内压爆破试验和高温水蒸气氧化试验。采用X射线衍射仪(X-ray Diffractometry,XRD)、扫描电子显微镜(Scanning Electron Microscope,SEM)和能量色散谱仪(Energy Dispersive Spectrometer,EDS)观察FeCrAl和FeCrAlY合金氧化产物成分、表面及截面氧化产物形貌,并对其成分进行分析。研究结果表明:微量Y主要固溶到FeCrAl合金包壳基体中,未形成Fe-Y第二相;固溶到FeCrAl合金包壳基体中的Y未对室温到1000℃内压爆破强度和破口形貌产生影响;但添加微量Y显著改善了FeCrAl合金包壳的耐高温水蒸气氧化性能,800℃、1000℃和1200℃水蒸气氧化8 h条件下,氧化增重量分别下降65.1%、60.0%和31.5%。相比于FeCrAl合金包壳表面单一的Al2O3氧化膜,FeCrAlY包壳表面形成了内部应力更低、致密性更高、且与基体结合力良好的含Y复合氧化膜。由此可见,微量Y的添加对FeCrAl合金的内压爆破性能未产生显著影响,但耐高温水蒸气氧化性能得到显著提高。[Background]FeCrAl alloy cladding,as an accident tolerant fuel(ATF)mid-term commercial technology approach,has received extensive attention.[Purpose]This study aims to investigate the effect of trace Y on the internal pressure burst and oxidation properties of FeCrAl alloy cladding.[Methods]Firstly,the crystalline grain size and micro-morphologies of FeCrAl and FeCrAlY alloy cladding samples were observed by optical microscope.Internal pressure burst and high temperature oxidation tests were carried out by burst test equipment and thermo-gravimetric analyzer with a moisture generator.Then,X-ray diffractometry(XRD),scanning electron microscope(SEM)and energy dispersive spectrometer(EDS)were employed to analyze the composition of oxidation products,surface and cross-sectional micro-morphologies of FeCrAl and FeCrAlY alloy cladding samples before and after high-temperature stream oxidation and the distribution of elements on the surface oxidation products.[Results]The results show that trace Y is mainly dissolved in the FeCrAl alloy matrix,and no Fe-Y phase is formed.The inclusion of Y do not change the burst strength and the rupture opening morphology at room temperature(RT)to 1000℃,and the high-temperature steam oxidation resistance of FeCrAl alloy cladding is significantly improved by the trace Y.Under the condition of steam oxidation at 800℃,1000℃and 1200℃ for 8 h,the oxidation weight gain of FeCrAlY alloy cladding decrease by 65.1%,60.0%and 31.5%,respectively.Compared with the single Al2O3 oxide film on the surface of FeCrAl alloy cladding,the Y-containing composite oxide film with lower internal stress,higher compactness and better adhesion with the substrate is formed on the surface of FeCrAlY alloy cladding.[Conclusions]Therefore,the addition of trace Y do not change the burst properties of FeCrAl alloy cladding,however,the high-temperature steam oxidation resistance of FeCrAl alloy cladding is significantly improved.

关 键 词：FECRAL 合金包壳 内压爆破 高温水蒸气氧化 氧化增重 

分 类 号：TL352.1[核科学技术—核技术及应用] TG174.444[金属学及工艺—金属表面处理]