α-Zr基体显微组织对新锆合金氧化膜的形成及其耐腐蚀性能的影响  

The effect ofα-Zr matrix microstructure on the formation of oxide film and the corrosion resistance of new zirconium alloys

作　　者：章海霞[1] 李中奎[2] 许并社[1] 王永祯[1] 周廉[2] 

机构地区：[1]太原理工大学新材料工程与技术研究中心,太原030024 [2]西北有色金属研究院,西安710016

出　　处：《功能材料》2014年第8期8062-8066,共5页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(51372160;51242007);山西省回国留学人员科研资助项目(2011-031);山西省留学人员科技活动择优资助项目([2011]762)

摘　　要：通过静态高压釜实验研究了NZ2、NZ8两种含Nb锆合金在400℃/10.3MPa蒸汽中的腐蚀规律;透射电镜及中子衍射对两种新锆合金α-Zr基体的显微结构进行分析;X射线衍射法、拉曼光谱法研究了它们在400℃蒸汽中腐蚀后氧化膜的晶体结构。腐蚀规律研究表明,400℃蒸汽中,NZ2合金的耐腐蚀性能较NZ8的好。α-Zr基体的显微结构研究显示,NZ2合金第二相粒子主要包括C14型Zr(Fe,Cr)2和Zr(Fe,Cr,Nb)2两种类型,α-Zr基体中固溶的Nb含量低于平衡固溶度;NZ8合金中只发现了一种Zr-Fe-Nb第二相粒子,Nb元素过饱和存在于α-Zr基体。氧化膜晶体结构研究显示,转折前氧化膜由四方相和单斜相组成,转折时,氧化膜内部出现了立方相,立方相的形成与Nb的添加密切相关;氧化膜中四方相含量越高,锆合金的耐腐蚀性能越好。大量Zr-Fe-Nb第二相粒子以及α-Zr基体中过饱和的Nb含量增加了NZ8合金氧化膜局部体积膨胀,促进了裂纹的生成,加速了氧化膜内部四方相向单斜相的转变,从而使腐蚀加速,而α-Zr基体中低于平衡固溶度的Nb含量及少量Zr(Fe,Cr)2和Zr(Fe,Cr,Nb)2第二相粒子使NZ2合金耐腐蚀性能相对较好。The corrosion kinetics of NZ2and NZ8alloys were investigated by static autoclave test in 400 ℃/ 10.3MPa steam;the matrix microstructures of the two alloys were tested by TEM and neutron diffraction method.The crystal structure of oxide films of NZ2and NZ8alloys after corroded was investigated by XRD and Raman spectra methods in this paper.The results of corrosion kinetics indicated that the corrosion resistance of NZ2alloy in 400℃/10.3MPa steam was better than that of NZ8alloy;TEM studies on the matrixes showed that the precipitates of NZ2were Zr（Fe,Cr）2and Zr（Fe,Cr,Nb）2,and Nb content in the matrix was less than solid solution limit.However,the precipitates of NZ8were Zr-Fe-Nb,and Nb was supersaturated in the matrix.The neutron diffraction result confirmed that the Zr（Fe,Cr）2 precipitates of NZ2matrix were C14structure.A great deal of Zr-Fe-Nb precipitates and the supersaturated Nb content in NZ8matrix increased the local volume expansion and accelerated the crack formation,which resulted in the higher corrosion rate of NZ8.Moreover,the less than solid solution Nb content in the matrix and Zr（Fe,Cr）2,Zr（Fe,Cr,Nb）2 precipitates improved the corrosion resistance of NZ2alloy.

关 键 词：耐蚀性能 NB含量 第二相粒子 氧化膜 α-Zr基体 

分 类 号：TB332[一般工业技术—材料科学与工程]