基于爆炸固结的低活化钢/钨功能梯度材料性能和复合机理研究

The integrity of the first wall is one of the key issues that constrain the nuclear fusion reactor. Tungsten, an excellent plasma-facing material, is the ideal candidate for first-wall construction when directly bonded to low-activation steel. However, due to the differences in thermal expansion coefficients, large thermal stresses occur during service, resulting in deformation of the interface mismatch, and leading to delamination, which seriously threatens the integrity of the first wall. The explosion consolidation, based on shock wave compaction sintering, has great advantages for solid particles that are difficult to be combined by conventional methods, and will not destroy the original performance of the powder particles in microstructure. Therefore, this project intends to select CLAM steel and tungsten as the research object. According to the non-linear principle and the inverse design system, the low activation steel / tungsten functionally graded material will be designed, and prepared by explosion consolidation. The properties and microstructure of the composites will be tested and characterized. Through the above research, we try to prepare the low activation steel/tungsten functional graded material; reveal the influence of the powder size, composition, mass and impact pressure on properties and microstructures of the low activation steel / tungsten functionally graded material; explore the compound mechanism of low activation steel and tungsten under the impact of explosion, and realize the direct connection between the fusion reactor structure material and plasma-facing material.

第一壁完整性是制约核聚变堆的关键问题之一。钨作为优秀的面向等离子体材料，直接与低活化钢连接是第一壁结构的理想候选形式。然而，由于第一壁面临高热负荷条件，热膨胀系数的差异会使低活化钢和钨在服役过程中产生巨大的热应力，造成界面变形错配、甚至脱层，严重威胁第一壁的完整性。基于冲击波压实烧结成型的爆炸固结法，对常规手段难复合的固体颗粒有极大优势，且不会破坏颗粒内部原先良好的微观组织。据此，本项目拟选取CLAM钢和钨作为研究对象，依据非线性模型和逆反设计系统，完成低活化钢/钨功能梯度材料的设计，采用爆炸固结法进行制备，并对复合材料的性能和微观组织结构进行测试与表征分析。通过以上研究，尝试制备出低活化钢/钨功能梯度材料，从宏观上揭示粉末尺寸、组分、质量及冲击压力对低活化钢/钨复合材料性能的影响规律，从微观上探索炸药爆轰作用下低活化钢/钨的复合机理，最终实现聚变堆结构材料和面向等离子体材料的直接连接。

第一壁完整性是制约核聚变堆的关键问题之一。钨作为优秀的面向等离子体材料，直接与低活化钢连接是第一壁结构的理想候选形式。本项目基于Wakashima非线性模型，采用逆反设计系统，根据复合材料热应力最小原则，对低活化钢/钨功能梯度材料的层数及组分进行了设计。选择从纳米级到毫米级不同梯度的粉末颗粒尺寸，并对粉末质量进行测量，并通过实验与模拟相结合的方式，准确预测不同距离处炸药爆炸产生的冲击波压力、炸药爆轰作用下飞板的加速运动历程，以及砧板产生的冲击压力。在制备出低活化钢/钨功能梯度材料后，固定飞板高度、飞板与砧板端面的距离以及砧板的直径，分别通过改变低活化钢、钨粉末颗粒的尺寸和质量、冲击压力，获得不同粉末尺寸和质量条件下的复合材料。并从密度、热导率、显微硬度、抗弯强度、层间剪切强度等，分析了粉末颗粒尺寸对低活化钢/钨功能梯度材料的性能影响规律，同时利用拉曼光谱、SEM、XRD等技术手段对微观结构进行表征，分析了粉末颗粒尺寸对低活化钢/钨复合材料的微观组织结构影响。