一种Zr基非晶/晶体复合型核材料的力学性能与耐腐蚀性能的研究

Enhanced mechanical properties and corrosion resistance of Zr-based amorphous/crystalline nuclear material

采用Zr65Cu35和Nb双靶直流共溅射方法,通过调节Nb靶的溅射功率,制备了不同Nb含量的Zr Cu Nb非晶薄膜。分别使用能谱仪、X射线衍射仪、高分辨透射电子显微镜观察Zr Cu Nb非晶薄膜的成分与结构,最终选择具有优异非晶形成能力的Zr53Cu38Nb9成分溅射到纯Zr基片上,以制备锆基非晶复合材料。研究测试Zr53Cu38Nb9非晶复合材料的力学性能与耐腐蚀性能。结果表明:与纯Zr基片相比,复合材料在弹性阶段力学性能无明显差异;而在塑性变形阶段,由于非晶薄膜与纯Zr基片的变形与断裂机制不同,该复合材料具有更好的拉伸塑性,其表现为非晶膜厚为280 nm、640 nm和960 nm的复合材料的最大拉伸塑性形变较纯Zr基片分别提高了2.72%、5.22%、4.27%;在耐腐蚀性能方面,非晶膜厚为640 nm的复合材料与纯Zr基片相比,具有较小的自腐蚀电流密度icorr、较正的腐蚀电位Ecorr以及较大的容抗弧半径,表现出更优异的耐腐蚀能力。因此,该新型Zr基复合材料在核材料领域具有潜在的应用。

Background： Zr-based alloys have been widely used as nuclear materials. However, enhancement of the resistance of particle radiation, the mechanical properties, and the corrosion resistance in alloys are still required. Purpose： The aim is to develop a new Zr-based nuclear material of excellent mechanical properties and corrosion resistance. Methods： DC magnetron sputtering method was applied to preparing ZrCuNb ternary amorphous films precipitated upon the pure zirconium substrate. The structure of ZrCuNb films was characterized using scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and high-resolution transmission electron microscope. Testing on mechanical properties such as tensile experiment was performed for both the ZrCuNb films/Zr substrate （the composite material） and the corresponding Zr metal plate. Corrosion resistance was studied using potentiodynamic polarization measurements. Results： It is found that full amorphous structure in films could be obtained microalloying Nb in ZrCu alloy, such as Zr53Cu38Nb9. In comparison with the Zr metal plate, the Zr substrate coated with Zr53Cu38Nb9 film does not have higher hardness or Young＇s modulus, however, the composite material possesses relatively high tensile strength and in particular obviously larger plastic-strain range. The enhancement is caused by the difference in initiation mechanism of cracks between the amorphous film and Zr substrate that they propagate along different orientations. Cracks in the substrate and film interfere with each other, leading to a delayed catastrophic rupture. In addition, the composite material has a stronger corrosion resistance. Conclusion： Zr metal plate coated with ZrCuNb amorphous film is a novel composite material with excellent mechanical properties and good corrosion resistance, which has a potential application in the nuclear engineering.