第二相粒子的析出演变及其对锆合金的影响研究进展

Research progress on precipitation evolution of second phase particles and effect in zirconium alloys

锆合金因具有低的热中子吸收截面、优异的抗腐蚀、蠕变及辐照性能,已广泛应用于核燃料组件中。为提高锆合金服役性能,通常加入微量Sn、Nb、Fe、Cr、Cu和Ni等合金元素,其中大部分合金元素在α-Zr中的固溶度较低,经过热机械加工后往往以金属间化合物的形式析出,形成第二相粒子(SPPs)。SPPs对锆合金的组织演化、力学性能等具有重要影响,细小且均匀分布的SPPs能有效提升锆合金的综合性能。本文结合锆合金的加工工艺,综述了国内外关于锆合金SPPs析出演变规律的研究进展,并提出了针对SPPs尺寸和分布的工艺优化方法;梳理了SPPs的类型、尺寸与分布以及晶体学特征,并阐明了SPPs析出后对锆合金塑性变形过程和再结晶行为以及力学性能的影响。最后,总结梳理了锆合金SPPs研究存在的问题及发展趋势,以期对锆合金的加工工艺优化提供参考。

The zirconium alloys have been widely used in nuclear fuel assemblies due to their low thermal neutron absorption cross section,excellent corrosion resistance,creep and irradiation properties.In order to improve the service properties of the zirconium alloys,trace alloying elements such as Sn,Nb,Fe,Cr,Cu and Ni are usually added into the alloys.The second phase particles(SPPs)are formed by precipitation of intermetallic compounds after thermo-mechanical processing,as most of the alloying elements have low solid solubility inα-Zr.The existence of the SPPs will have an important influence on the microstructure evolution and mechanical properties of the alloys.Fine and uniformly distributed SPPs can effectively improve the comprehensive properties of the zirconium alloys.In this paper,the precipitation and evolution of the SPPs were reviewed based on the processing technology of the zirconium alloys,process optimization methods for size and distribution of the SPPs were proposed.The type,size and distribution,and crystallographic characteristics of the SPPs were obtained.And the effects of the SPPs on the plastic deformation,recrystallization and mechanical properties of the zirconium alloys were also discussed.At last,the existing problems and development trends of the SPPs were summarized that wish to provide some references for microstructure controlling during the thermo-mechanical processing of the zirconium alloys.