Layered metal/silicon carbide (SiC) materials systems are becoming increasingly relevant to solve materials challenges in advanced fission and fusion nuclear energy systems, necessitating a deeper understanding of how interfaces between dissimilar materials behave under high energy irradiation. In this work, we use a Cr-SiC bilayer system as a model to study the behavior of such interfaces under high energy ion irradiation (80 MeV Xe ions) at elevated temperatures (∼350 °C). Through high resolution characterization of the interface, we observed the formation of a nanoscale Cr-rich amorphous layer adjacent to crystalline SiC. We explain this phenomenon through a multi-scale computational approach incorporating ballistic mixing simulations, density functional theory calculations, and CALPHAD-based non-equilibrium modeling that shows the localized amorphization of Cr to be driven by the synergistic action of irradiation-induced point defects within Cr and transport of Si and C atoms across the interface. In particular, the accumulation of radiation damage results in the thermodynamic destabilization of the point-defect containing, metastable Cr-Si-C solid solution with respect to an amorphous phase of identical composition. This study advances the understanding of how metal/SiC interfaces behave under irradiation and establishes a modeling framework that can be applied to interfacial systems to understand irradiation-induced amorphization.

中文翻译：

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高能辐照下金属铬与碳化硅界面的异常纳米级非晶化


层状金属/碳化硅（SiC）材料系统对于解决先进裂变和聚变核能系统中的材料挑战变得越来越重要，因此需要更深入地了解不同材料之间的界面在高能辐射下的行为方式。在这项工作中，我们使用 Cr-SiC 双层系统作为模型来研究在高温（~350 °C）高能离子辐照（80 MeV Xe 离子）下此类界面的行为。通过界面的高分辨率表征，我们观察到与晶体 SiC 相邻的纳米级富 Cr 非晶层的形成。我们通过多尺度计算方法解释了这一现象，该方法结合了弹道混合模拟、密度泛函理论计算和基于 CALPHAD 的非平衡建模，该模型显示 Cr 的局部非晶化是由辐照引起的点缺陷的协同作用驱动的Cr 以及 Si 和 C 原子穿过界面的传输。特别是，辐射损伤的累积导致含有点缺陷的亚稳Cr-Si-C固溶体相对于相同组成的非晶相的热力学不稳定。这项研究增进了对金属/SiC界面在辐照下如何表现的理解，并建立了一个可应用于界面系统以了解辐照引起的非晶化的建模框架。