Background: Zirconium alloys are widely used as cladding tube and structural materials in pressurized water reactors because of their low thermal neutron cross section, good mechanical properties and corrosion resistance. At present, the main problem in the development of domestic zirconium alloys is the development of new zirconium alloys with independent intellectual property rights, and improving the corrosion resistance and hydrogen pick-up behaviors of zirconium alloys, making them significantly better than Zr-4 alloy, at the same time, keeping comparable mechanical properties, radiation growth and creep resistance with Zr-4 alloy.Purpose: Therefore, a series of various model zirconium alloys were prepared by vacuum arc smelting based on Zr-Sn-Nb alloy with minor alloying elements such as Ge and Si, in order to select the most promising candidate alloys to meet these requirements, via comparative studies on the corrosion resistance, hydrogen pick-up behaviors and mechanical properties. Methods:Transmission electron microscopy (TEM) was used to characterize the detail microstructure of base alloys. Corrosion resistance was examined by the weight gain in static autoclave with different water chemistry environments. Hydrogen pick-up behaviors were directly reflected by the hydrogen contents across the oxidation layers and underneath matrix measured by hydrogen determinator. The mechanical properties were evaluated by conventional tensile testing.Results: It was found that SZA-6 and SZA-4 alloys consisted of fully recrystallized grain structures with uniformly distributed fine second phase particles located within grain interior and at grain boundaries. Both SZA-4 and SZA-6 alloys exhibited excellent corrosion resistance in all three water chemistry conditions. The corrosion resistance of SZA-6 was better than the reference commercial alloys, and SZA-4 was slightly better than SZA-6. However, the SZA-6 alloy seemed to be less susceptible to hydrogen pick-up compared to SZA-4 alloy. In addition, the mechanical properties of two new zirconium alloys met the design criterion.Conclusion: Considering the outstanding corrosion resistance and low hydrogen pick-up in simulated water chemistry conditions and satisfied mechanical performances, the SZA-4 and SZA-6 alloys were suggested as promising alloys used for CAP1400 fuel assembly in the future.%在Zr-Sn-Nb系合金的基础上添加微量合金元素Ge和Si等,采用真空电弧熔炼,制备了多种新锆合金.使用透射电子显微镜(Transmission electron microscope,TEM)对合金基体进行显微组织分析,分别通过堆外高压釜腐蚀试验、定氢分析仪和万能材料试验机对合金的腐蚀、吸氢和拉伸性能进行评估.结果表明,常规工艺处理后,SZA-4和SZA-6合金均发生了完全再结晶,第二相细小、均匀弥散分布在晶粒内和晶界上;SZA-4和SZA-6合金在三种水化学条件下均具有优良的耐腐蚀性能,SZA-6合金的耐腐蚀性能优于参考合金,SZA-4合金的耐腐蚀性能略优于SZA-6合金;SZA-6合金的吸氢性能略优于SZA-4合金;两种合金的拉伸性能满足设计要求.基于SZA-4和SZA-6合金优良的耐腐蚀、吸氢和力学性能,未来将有望用于CAP1400自主化燃料组件.
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