钨与低活性铁素体钢纳米梯度复合连接与界面行为

Tungsten （W）is the optimal high heat load resistance material of plasma-facing divertor in China Fusion Engineering Testing Reactor (CFETR) and future fusion demonstrate reactor (DEMO), reduced activation ferrit steel (RAFM) has been chosen as the main heat sink and structural material. The surface temperature of tungsten can reach as high as 2000℃ when tungsten divertor endures a transient heat flux of 20MW/m2, while its cooling end temperature is just about 130℃. So the high-strength joining of tungsten with RAFM is the key for rapid heat leading. Due to the differences in physical and chemical properties of tunsgten and RAFM, in particular, a big difference in thermal expansion coefficient, high thermal stresses would generate in connecting process when conventional high temperature diffusion bonding and brazing method were used, the stress in the connecting components will lead to the thermal stress failure under repeated thermal exchange service environment. In this project, nano composite - gradient transition - diffusion sintered technology will be usesd to achieve the goog metallurgical bonding and joining between tungsten and RAFM, gradient composite structures and processes willed be investigated and optimized. In addition, the first-principles will be employed to calculate the interface elements binding energy of gradient nano-composite interlayer, so as to predict and explain the behavior of nano- gradient composite interfacial bonding , establish the functinal mechanism. The ultimate goal is to provide technical support for preparation of plasma facing components in CFETR, DEMO.

钨（W）是中国聚变工程实验堆（CFETR）和未来聚变示范堆（DEMO）面向等离子体偏滤器最理想的抗高热负荷材料，低活性铁素体钢（RAFM）被选择为主要的热沉结构材料。钨偏滤器承受高达20MW/m2瞬态热通量冲击时其钨表面温度2000℃以上，冷却端温度130℃左右，钨与RAFM材料高强度连接成为快速热疏导的关键。由于W与Fe物理化学性能的差异，特别是热膨胀系数相差很大，传统高温扩散连接以及钎焊等方法在连接过程中产生高的热应力，从而容易导致部件在反复冷、热交换热负载服役环境下产生热应力失配。本项目采用纳米梯度复合过渡-扩散烧结实现钨与低活性铁素体钢良好的冶金结合与连接，研究优化梯度复合结构与工艺，用第一性原理计算纳米复合梯度过渡层连接其界面元素的结合能，预测和解释其纳米梯度复合界面结合行为，建立其作用机制，为CFETR、DEMO面向等离子体部件制备提供技术支撑。

钨（W）是中国聚变工程实验堆（CFETR）和未来聚变示范堆（DEMO）面向等离子体偏滤器最理想的抗高热负荷材料，低活性铁素体钢（RAFM）被选择为主要的热沉结构材料。钨偏滤器承受高达20MW/m2瞬态热通量冲击时其钨表面温度2000℃以上，冷却端温度130℃左右，钨与RAFM材料高强度连接成为快速热疏导的关键。由于W与Fe物理化学性能的差异，特别是热膨胀系数相差很大，传统高温扩散连接以及钎焊等方法在连接过程中产生高的热应力，从而容易导致部件在反复冷、热交换热负载服役环境下产生热应力失配。为解决W与RAFM连接难题，本项目设计纳米梯度复合过渡，研究优化了纳米梯度过渡结构及连接工艺，最终实现了钨与低活性铁素体钢良好的冶金结合连接，制备出了完整的连接部件。采用用第一性原理计算了纳米梯度复合界面结合行为和辐照损伤行为，建立了界面结合作用机制和辐照损伤机制。研究结果为未来聚变堆面向等离子体部件制备提供技术储备，同时扩展到航空航天、国防军工领域，为高温钨钼材料与结构钢的连接提供技术支持。