核燃料贮运用新型B4C/Al中子吸收材料高效制备及成型基础研究

B4C/Al, as a new neutron absorber material, has been gradually replacing traditional materials such as boron steel for use in storage and transportation equipments of nuclear fuel. However, in our country, it has always been dependent on imports, which has severely hampered the pace of independent nuclear power construction. According to the wet storage and the development trend of new type of dry storage for nuclear fuel, the current project will investigate the key problems on the production, fabrication and performance of B4C/Al material, such as the design basis for raw materials, the efficient and controllable preparation mechanism of billets and molding parts, and the performance optimization mechanism of corrosion and high temperature endurance in service. The design principles for the B4C particle parameters, Al matrix compositions and nano phases with high temperature resistance will be investigated. The effect mechanisms of raw materials and billet preparation processes on the interfacial reactions and the formability and performance of the composites will be evaluated. By combining the multi-scale simulation methods with the experimental verification, the evolution mechanisms and controlling methods of the deformation structures and defects will be analyzed. The corrosion and protection mechanisms of the composites under different service conditions, and high-temperature creep behaviors and strengthening mechanisms will be clarified. Besides, practical friction stir welding tools will be developed, and the formation mechanisms and control methods of welding defects will be explored. Eventually, the whole chain of control of B4C/Al from design, preparation, forming to service and the high-efficient manufacture will be achieved. The localization of B4C/Al batch preparation process will be promoted by cooperating Liaoning Zhong Wang Group Co., Ltd. This will provide strong supports for the transformation of the conventional industries in Liaoning province to high-tech industries.

B4C/Al作为新型中子吸收材料，正逐渐替代传统硼钢等材料用于核燃料贮运设备。但我国一直依赖进口，严重制约核电自主建设步伐。本项目依据核燃料湿法贮存及新型干式贮存发展趋势，针对B4C/Al高效制备亟待突破的原料设计准则、坯锭与型件的可控制备机理、服役中耐蚀与高温持久性能优化机制等关键问题开展研究。主要研究B4C颗粒参数、铝基体成分与耐高温纳米相的设计原理；探讨原料选型、坯锭制备工艺对界面反应行为及复合材料成型性与服役性的影响机制；采用多尺度模拟结合实验验证，分析变形加工组织与缺陷的演化机制与控制方法；研究不同服役工况下材料腐蚀与防护机理、高温蠕变行为与强化机制；研制实用化的搅拌摩擦焊接工具，探讨焊接缺陷形成机制与控制方法。通过这些研究，实现B4C/Al从设计、制备、成型到服役的全链条控制与高效制备，并联合辽宁忠旺集团共同推进B4C/Al国产化进程，为辽宁省支柱产业向高技术转型提供有力支持。

B4C/Al中子吸收材料是核燃料贮存和运输过程中维持次临界状态的关键材料，我国B4C/Al材料长期依赖进口，阻碍了核电设备自主化进程。本项目以B4C/Al高效制备为核心目标，通过对功能型B4C/6061Al中颗粒含量、尺寸、纯度、基体成分、热压工艺对复合材料微观结构和力学性能影响进行系统研究，确定了原材料选择与成分设计准则；建立了塑性变形加工中B4C颗粒分布均匀性与缺陷控制模型，从而突破了板材高效轧制难题；对更新型的高温结构功能一体化(B4C+Al2O3)/Al中子吸收材料的不同制备工艺路线开展研究，阐明了纳米Al2O3高温强化机制；通过对界面、第二相等微观结构表征，阐明了B4C/6061Al中界面反应机制、反应产物类型和形态及其对高温强度的增强作用；利用自主研发的高韧耐磨焊接工具对B4C/6061Al和(B4C+Al2O3)/Al进行搅拌摩擦焊接研究，阐明了焊接工具形状、焊接工艺等对接头微观结构和力学性能的影响；对B4C/6061Al进行了加速腐蚀、高温老化和加速辐照实验，验证了该材料在服役条件下的可靠性，并利用TEM下的准原位实验阐明了腐蚀机理及腐蚀过程中材料内部各相的界面、元素变化。通过以上研究，打通了B4C/Al从设计、制备、塑性加工和焊接成型的全链条工艺流程并完成验证实验，为B4C/Al中子吸收材料的国产化发展提供了理论与技术支持。