Design of novel interlayers in W-W diffusion-bonded joints for large nuclear shielding components applications

核聚变反应堆内的环境非常苛刻。氘和氚之间的聚变反应在等离子体中释放出约16.6MeV的能量，分为高能中子（~ 14 MeV）和带电氦核。中子辐照对反应堆中的高温超导体（HTS）的破坏尤为严重。因此，制造了由W材料制成的屏蔽件，目的是保护HTS免受中子辐射以及来自等离子体的热疲劳负载。由于形成脆性金属间相和高残余应力，连接W屏蔽组件已被证明具有挑战性。因此，尚未开发成功的连接方法。这个为期3年的博士职位将开发一个有效的连接W组件，利用物理气相沉积和扩散结合作为连接方法沉积的涂层夹层。涂层中间层的化学成分和扩散结合参数将通过集成计算材料工程（ICME）方法，通过高通量热力学预测（Thermo-Calc，CALPHAD），有限元分析（Abaqus）和实验验证的组合进行优雅的设计。这项工作将涉及在整个项目中与工业赞助商英国原子能管理局（UKAEA）的密切合作。

The environment within nuclear fusion reactors is very demanding. The fusion reaction between deuterium and tritium releases approximately 16.6MeV of energy within a plasma, subdivided between a high-energy neutron (~14MeV) and a charged helium nucleus. Neutron irradiation is particularly damaging to the high temperature superconductors (HTSs) in the reactor. A shield, made of W material, is therefore manufactured with the aim to protect the HTS from neutron radiation, as well as thermal fatigue loads from the plasma. Joining W shielding components has proven challenging, due to formation of brittle intermetallic phases and high residual stresses. Consequently, a successful joining methodology has not yet been developed. This 3-year PhD position will develop an effective joint for W components, utilising a coating interlayer deposited by Physical Vapour Deposition and diffusion bonding as joining method. The chemistry of the coating interlayer and diffusion bonding parameters will be elegantly designed by an Integrated Computational Material Engineering (ICME) approach, through a combination of high-throughput thermodynamic predictions (Thermo-Calc, CALPHAD), Finite Element Analysis (Abaqus) and experimental validations. The work will involve a tight collaboration with the UK Atomic Energy Authority (UKAEA), the industrial sponsor, throughout the project.