纳米结构锆合金组织氧化膜结构演变的XRD分析

Evolution of Microstructure of Oxide Film of Nano-Crystalline Zircaloy-4

利用X射线衍射(XRD)方法研究了纳米结构锆-4合金在400℃水腐蚀过程中氧化膜结构的演变特征,进而考察组织纳米化对锆-4合金抗腐蚀性能的影响。研究结果表明,纳米组织锆-4合金的氧化膜结构演变趋势类似于普通锆-4合金。然而,纳米化处理使合金表层组织向(101)、(102)等低指数面产生了显著的择优取向;纳米面形成的氧化膜中,其ZrO2的晶粒尺寸小于普通粗晶面形成的氧化膜中的ZrO2晶粒尺寸;实验结果还显示,纳米化后锆-4合金组织氧化膜中四方ZrO2向单斜ZrO2转变的速率小于普通组织形成的氧化膜中的转变速率。本文对纳米化处理导致锆-4合金腐蚀动力学过程和结构演变细节的变化进行了初步的分析和讨论。

In this paper the evolution characteristics of the microstructure of the oxide film of nanocrystalline zircaloy-4 have been studied with x-ray diffraction （XRD） technology. The oxide film is formed in water corrosion circumstance at 400℃. The results show that the evolution of the oxide film structure of nano-crystalline zircaloy-4 is similar to that of the normal zircaloy-4 with coarse grain size. However, the preferred orientation in nano-crystalline zircaloy-4 is found at low exponential plane, such as （101） and （102）. The grain size of the oxidation film of nano-crytalline ZrO2 is smaller than that of the normal crystalline plane. The experimental results also show that the transformation speed rate from tetragonal phase （t-ZrO2） to monoclinic phase （m-ZrO2） in the oxide film of nano-crystalline zircaloy-4 is less than that in the oxide film of normal zircaloy-4 with coarse grain size. Thus, the nano-crystallized treatment can result in the changes of the corrosion dynamics process of the zircaloy-4 alloy. And these changes have been discussed in the paper.