基于同步辐射技术的Si含量影响熔盐堆镍基焊丝蠕变损伤行为的机理研究

小型模块化的熔盐堆是一个环境适应强和有发展前途的多用途反应堆。该反应堆用的UNS N10003合金配套焊材的高温持久强度断裂因子R较低仅为0.67，这制约着熔盐堆的经济性发展方向，因此，亟需发展蠕变性能优异的配套焊材。本项目提出“Si含量对焊接性和高温蠕变性能的影响”这一科学研究，拟采用同步辐射微束荧光、衍射和吸收谱的集成技术对不同Si含量焊缝中各种碳化物的成分、结构和形貌进行精细表征，采用白光劳尔微区衍射技术，研究熔敷金属中碳化物与基体的取向关系，焊接性和蠕变裂纹周围晶粒的微观应力/应变的变化关系，结合常规的电子显微技术结果，阐明Si含量对焊接性、组织和持久性能的作用机理，建立起“Si含量-碳化物-持久性能”的经典材料学构型关系，优化焊丝中Si含量，为提高焊缝R值提供坚实的理论基础。

The miniaturized and modularized molten salt reactor is a multi-purpose reactor with strong environmental adaptability and promising development. The R (high-temperature endurance strength fracture factor) of the UNS N10003 alloy supporting welding materials used in the reactor is only 0.67, which restricts the economic development direction of the molten salt reactor. Therefore, it is urgent to develop supporting welding materials with excellent creep performance. This project proposes the scientific research of "The effect of Si content on the weld structure and high temperature creep performance". It is intended to adopt the integrated technology of synchrotron radiation microbeam fluorescence, diffraction and absorption spectrum to finely characterize the composition, structure, and morphology of various carbides in welds with different Si contents. Besides, the white light Raul micro-domain diffraction technology will be applied to investigate the relationship between the carbide and the matrix during the creep of the weld and the micro-stress / strain change of the grains around the crack. Combined with the results of conventional electron microscopy, the mechanism of Si content on the weld structure and endurance performance will be clarified and the classic material configuration relationship of "Si content-carbide-endurance performance" will be established. By optimizing the Si content in the welding wire, it provides a solid theoretical basis for improving the R of the weld.