Nb对Zr-Sn系锆合金腐蚀各向异性行为的影响规律及其机理研究

项目名称： Nb对Zr-Sn系锆合金腐蚀各向异性行为的影响规律及其机理研究

项目编号： No.51471102

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 姚美意

作者单位： 上海大学

项目金额： 85万元

中文摘要： 由于锆合金是密排六方金属，并且在其加工成材的过程中会产生织构，所以其氧化膜生长的各向异性是腐蚀过程中的一个基础问题。本项目选用2-3 mm厚的Zr-0.7Sn-xNb-0.35Fe-0.15Cr（x=0-1.0）合金板状样品为研究用材料，通过测定样品轧面(SN)，垂直于轧向的截面(SR)和垂直于横向的截面(ST)上腐蚀形成的氧化膜厚度随腐蚀时间的变化，研究添加Nb对Zr-Sn系锆合金在不同水化学条件下腐蚀各向异性行为的影响规律。通过研究织构取向因子不同的SN、SR和ST面上的合金元素在表面和晶界处的偏聚行为、以及在SN、SR和ST面上腐蚀形成的氧化膜和O/M界面处的显微组织特性及其在腐蚀过程中的演化，揭示添加合金元素Nb可以抑制Zr-Sn系锆合金腐蚀各向异性的机理，以及Nb含量影响Zr-Sn-Nb锆合金腐蚀行为的本质原因。为开发具有我国自主知识产权的新锆合金提供理论依据和指导。

中文关键词： 锆合金；腐蚀；各向异性；合金元素Nb；显微组织

英文摘要： Zirconium alloys are an important structural material used for fuel cladding. Zirconium alloys with a hexagonal close-packed crystal structure have prominent anisotropic characteristic and a strong texture is produced in sheet or tubular materials during the fabrication process. The anisotropic characteristic is bound to be reflected on the corrosion behavior and the texture will influence the corrosion resistance of zirconium alloys. In this project, Zr-0.7Sn-xNb-0.35Fe-0.15Cr（x=0-1.0）alloy sheet specimens with 2-3 mm in thickness will be adopted for the experimental materials. By measuring the oxides thickness on the rolled surface (SN), the surface (SR) perpendicular to rolling direction and the surface (ST) perpendicular to transversal direction as a function of exposure time, the effect of adding Nb on the anisotropic oxidation of Zr-Sn zirconium alloys will be investigated in different water chemistries. The segregation behavior of alloying elements on the outer-surface and at the grain boundaries on different surfaces of SN, SR and ST will be studied. The microstructures and their evolution of oxides and O/M interface formed on different surfaces of SN, SR and ST will also be investigated. Based on these investigations, the mechanism on adding Nb suppressing the anisotropic oxidation of Zr-Sn zirconium alloys and on the effect of Nb content on the corrosion behavior of Zr-Sn-Nb zirconium alloys will be illustrated. These results will provide theoretical evidence and a guide in developing advanced zirconium alloys with our own independent intellectual property.

英文关键词： zirconium alloy;corrosion;anisotropic behavior;alloying element Nb;microstrucure