基于强流脉冲离子束辐照评估TiH2膜的损伤机制

Metal hydride (MHx) is typically under extreme non-equilibrium irradiations when used as a neutron moderator in nuclear reactor, an ion source in laser, a target material for neutron generator, and other devices. Therefore, for the sustainable development and applications of metal hydride in the above areas, it is important to investigate metal hydride damage mechanisms under irradiation of non-equilibrium beams. This work proposes using an extreme non-equilibrium high intensity pulsed ion beam (HIPIB) to evaluate the effects on damage mechanisms of titanium hydride (TiH2) film under irradiation. In the experiments, it is proposed to investigate the effects of HIPIB on: (1) the “selective ablation” pattern of TiH2 film surface, (2) TiH2 film surface phase-transition and thermal decomposition, (3) release amount of H from the film surface and its re-distribution, and (4) change patterns of the film-substrate binding strength. In numerical simulations, the “selective ablation” physical model description of the TiH2 film surface under HIPIB irradiation will be developed and the spatial-time dependent plots of temperature-stress field of TiH2 film will be generated and analyzed, and the related experimental phenomenon will also be explained. The goal is to understand the damage mechanisms of TiH2 film irradiated by extreme non-equilibrium beams, and to build the experimental and theoretical foundations for the prolonged lifetime of TiH2 film under irradiation of extreme non-equilibrium beams.

金属氢化物（MHx）应用于反应堆中子慢化剂、激光离子源片材料、中子发生器用靶时，通常会经历极端非平衡束流的辐照，因此研究非平衡束流辐照下 MHx 的损伤机制是满足其在上述领域可持续发展的迫切需要。本项目提出利用具有极端非平衡效应的强流脉冲离子束辐照 TiH2 膜，评估极端非平衡束流对膜的损伤机制。实验上，拟研究强流脉冲离子束：（1）致 TiH2 膜表面“择优烧熔”规律；（2）致膜面 TiH2 的相变、热分解规律；（3）辐照后膜面 H 的释放量和再分布规律；（4）致膜-基体结合强度失效的规律。模拟计算上，建立强流脉冲离子束致 TiH2 膜面“择优烧熔”的物理模型，获得束流辐照下膜内温度-应力场时空演化图像，并以此解释相关的实验规律。最终实现深化对极端非平衡束流致 TiH2 膜损伤机制的认识，可为延长 TiH2 膜在极端束流条件下的使用寿命奠定实验和理论基础。

本研究主要针对束靶相互作用过程中的关键物理现象，研究束靶相互作用过程，主要讨论极端束流条件下离子束对氘钛膜热损伤和辐射损伤方面影响的变化规律。通过开展脉冲离子束致氘钛膜损伤特性的实验研究，揭示了束流对氘钛膜表面形貌、物相结构、辐照缺陷方面影响的变化规律，并结合束靶相互作用的热-力耦合效应与辐射损伤效应的数值建模，进一步探明束靶相互作用过程中的物理机制。