Nanostructural Y-Zr-O complex oxide dispersion-strengthened (ODS) Mo alloys are designed for accident-tolerant fuel cladding. The phase and morphology evolution of ODS Mo powders during mechanical alloying (MA) and annealing were studied. The dissolution and reprecipitation mechanisms were revealed by quantitative calculation of dissolved Y and Zr amounts, thermodynamics and dynamics analysis, and phase analysis. The results reveal MA induces Mo grain refinement and a high density of dislocations in powders, facilitating the dissolution of YO and MoZr and the formation of Mo supersaturated solid solution, rather than the negative mixing heat. By subtracting vacancies and oxygen effects, the dissolved amount is estimated as 2.2 at.% Y and 1.8 at.% Zr after 96 h-milling. During annealing, the Y-Zr-O complex oxide is precipitated in Mo-10 wt%YO powders above 900 °C since the introduced ZrO contamination during MA, and then cubic-YO beyond 1100 °C. The findings provide a scientific basis for controlling Y-Zr-O complex oxide nanoprecipitates and optimizing the service performance of Mo alloys.

中文翻译：

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Y-Zr-O复合氧化物弥散强化（ODS）Mo粉在机械合金化和退火过程中的物相和形貌演变


纳米结构 Y-Zr-O 复合氧化物弥散强化 (ODS) Mo 合金专为耐事故燃料包壳而设计。研究了机械合金化 (MA) 和退火过程中 ODS Mo 粉末的物相和形貌演变。通过溶解Y和Zr量的定量计算、热力学和动力学分析以及物相分析揭示了溶解和再沉淀机制。结果表明，MA 会细化 Mo 晶粒并提高粉末中的位错密度，促进 YO 和 MoZr 的溶解以及 Mo 过饱和固溶体的形成，而不是产生负混合热。通过减去空位和氧的影响，96 小时研磨后溶解量估计为 2.2 at.% Y 和 1.8 at.% Zr。在退火过程中，由于在 MA 过程中引入了 ZrO 污染，Y-Zr-O 复合氧化物在高于 900 °C 的温度下在 Mo-10 wt%YO 粉末中沉淀，然后在超过 1100 °C 的温度下沉淀出立方-YO。该研究结果为控制Y-Zr-O复合氧化物纳米沉淀和优化Mo合金的使用性能提供了科学依据。