钨/钽层状复合材料的界面结构演变微观机制及强韧化机理

Tungsten plays an irreplaceable role in the applications of high temperature and irradiation environment. However, the processing performance and applications fields are limited by the low temperature brittleness and recrystallization brittleness of tungsten. It is expected that the dissimilar metal layered composites composed of tungsten and other metals can greatly improve the strength, toughness, microstructure thermal stability and radiation resistance of tungsten. This project intends to study the microstructure and properties of W/Ta layered composite material systematically. The study focuses on the evolution of interface microstructure of W/Ta layered composites during Spark Plasma joining and rolling process. Firstly, the study will investigate the interface microstructure and properties of W/Ta composites during Spark Plasma joining to determine the relationship between the properties and the process of joining and the orientation relationship between Ta and W. Secondly, the microstructure and properties of W/Ta composties will be studied during cold rolling. The W/Ta interfacial structure and the orientation relationship between Ta and W will be investigated to propose the evolution model of W/Ta interface. Thirdly, the study will determine the relationship between microstructure and the mechanical properties of materials and clarify the effects of grain boundaries, dislocation boundaries and phase interface on the mechnical properties to reveal the strengthening and toughening mechanism of W/Ta laminated composite. Above all, this study will provide technological foundation and theory evidence for designing and manufacturing tungsten based laminate composite materials with high strength, high toughness and high temperature stability.

金属钨在高温和辐照等极端服役环境中具有不可替代的作用，然而钨的低温脆性和再结晶脆性使其加工性能和应用范围受到限制。钨与其他金属韧化层组成的层状复合材料有望能大幅提高钨的强度、韧性、组织热稳定性和抗辐照性能。本项目拟以钨/钽层状复合材料为研究对象，研究钨/钽层状复合材料在放电等离子体连接过程中的钨/钽界面结构和性能，确定连接工艺与材料性能之间的对应关系，揭示钨/钽界面形成机理及其晶体学取向关系；研究复合材料在轧制变形过程中钨/钽界面结构和性能演变规律，揭示钨/钽界面晶体学取向关系演变微观机制；探明各种界面（包括晶界、位错界面和相界面）的强化和韧化作用，揭示钨/钽层状复合材料的强韧化机理，构建材料微观组织结构与力学性能之间对应关系，从而为设计和制备高强度、高韧性及耐高温钨基层状增韧复合材料提供技术基础和理论依据。

金属钨在高温和辐照等极端服役环境中具有不可替代的作用，然而钨的低温脆性和再结晶脆性使其加工性能和应用范围受到限制。钨与其他金属韧化层组成的层状复合材料能大幅提高钨的强度、韧性和组织热稳定性等。本项目：1）设计制备了钨/钽层状复合材料，利用不同的放电等离子体连接工艺参数，在不同的连接温度下制备了界面结合良好的钨/钽层状复合材料，并详细研究了钨/钽各层的组织以及界面微观结构及晶体学取向关系，构建了钨/钽之间的界面模型；2）研究了连接温度对钨/钽层状复合材料的力学性能的影响，测试了不同温度下连接的钨/钽复合材料的力学性能，获得了复合材料制备工艺、微观组织与力学性能之间的关系；3）研究了钨/钽层状复合材料在热加工变形过程中的钨/钽界面组织和性能，研究了钨/钽各层的组织以及界面微观结构及晶体学取向关系，构建了钨/钽之间的界面模型；4）在上述基础上，对拉伸后的样品，观察不同状态下钨/钽层状复合材料的断口形貌，并通过半原位的方法分析了裂纹源及其扩展路径，研究了材料的断裂机制，分析了钨层、钽层和界面对材料的韧化作用。最后，构建了不同温度下制备的钨/钽层状复合材料的强度模型和断裂模型，解释了复合材料的强韧化机理。优化的混合强度模型很好的预测了钨/钽层状复合材料的强度。通过本项目的研究，提高了钨材料的韧性，为设计和制备高强度、高韧性及耐高温钨基层状增韧复合材料提供了技术基础和理论依据。