锆合金焊接技术的研究现状与展望

A Review： Status Quo and Prospect on Welding Techniques of Zr Alloys

摘要:

近年来，清洁核能发展迅速，锆合金因其耐腐蚀性能好、中子吸收截面小等优势被用作水冷核反应堆的燃料元件包壳材料。燃料组件装配过程中，通常采用焊接方法将核燃料密封在锆合金包壳内。其中，传统熔焊的热输入高，焊后易出现变形超差，钎焊过程中易产生气孔和连续分布的金属间化合物（intermetallic compounds，IMCs）损害接头性能，而采用低温扩散焊可以避免上述问题的出现。为此，本文分析了锆及锆合金的焊接性，综述了锆合金熔焊、钎焊和扩散焊等焊接技术的国内外研究现状，阐述了两种焊前优化方法，即表面机械研磨处理（surface mechanical attrition treatment，SMAT）和热氢处理技术（thermo-hydrogen processing，THP），最后对其在锆合金的低温扩散焊的应用进行总结和展望。

Abstract:

In recent years, clean nuclear energy has developed rapidly. Zr alloys are commonly used as fuel element cladding materials in water-cooled nuclear reactions due to their good corrosion resistance and low neutron absorption cross-section. The nuclear fuel is usually sealed in a Zr alloy envelope by welding, so its weld quality is particularly critical. The high heat input of traditional fusion welding leads to large deformation, and the porosity and intermetallic compounds (IMCs) in the brazing process tend to damage the joint performance, and low-temperature diffusion bonding of Zr alloys can avoid the above problems. Therefore, this paper analyzed the weldability of Zr and its alloys, reviewed the research status of their welding technologies including fusion welding, brazing, and diffusion bonding, briefly introduced two kinds of pre-welding optimization methods, namely surface mechanical attrition treatment (SMAT) and thermo-hydrogen processing (THP). Finally, it summarized and prospected the applications in low-temperature diffusion bonding of Zr alloys.