锆合金具有优异的耐腐蚀性能，主要被用作水冷核反应堆的堆芯结构材料，由第二相粒子引发的氧化膜损伤开裂行为是制约这类材料发展的关键原因之一。针对锆合金氧化膜本身的复杂性和应力分布影响因素的多样性，本项目拟以含单一类型第二相粒子的Zr-Nb-Fe合金为研究对象，围绕氧化膜应力状态及损伤开裂行为深入开展研究。通过研究氧化膜宏观应力和微区应力分布的演化过程，氧化膜中不同位置的第二相粒子及其周围氧化膜的微结构特征，以及氧化膜中裂纹的萌生规律，揭示第二相粒子类型—应力分布变化—氧化膜损伤开裂行为之间的内在联系。并建立多参数三维有限元模型，深入分析第二相粒子的氧化速度，弹性模量和氧化体积膨胀率对应力变化的影响，深层次探讨氧化膜损伤开裂机理，实现对Zr-Nb-Fe合金氧化膜裂纹萌生的有效控制，为高性能核用锆合金的设计和制备提供理论支撑。

Zirconium alloys, which serve as water cooled reactor core structure material, possess excellent corrosion resistance. One of the important reasons for limiting the development of these materials is the damage and cracking behavior in their oxide triggered by second phase particles (SPPs). Depending on the complexity of oxide film on zirconium alloys and diversity of influencing factors in the stress distribution, this proposal focuses mainly on the Zr-Nb-Fe alloys which containing single type SPPs, and following cracking behavior and stress state in oxide scale are studied. By investigating the evolution of macro-stress and micro-stress distribution in oxide, the microstructure characteristic of SPPs and their nearby oxide, rule of crack initiation in oxide, and then the relationships among SPPs, variation of stress distribution and the damage and cracking behavior in oxide are researched. In addition, in order to analyze the effect of oxidation rate, elastic modulus and oxidation volume expansion ratio of SPPs on variation of stress in oxide deeply, multi-parameters three-dimensional finite element models are built, which achieves the controllability of crack initiation in the oxide of Zr-Nb-Fe alloys and provides theoretical support for designing and preparing high performance nuclear zirconium alloys.