Multi-Scale microscopy of Reactive sintered boride (RSB) neutron shielding materials
Multi-Scale microscopy of Reactive sintered boride (RSB) neutron shielding materials
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反应烧结硼化物 (RSB) 中子屏蔽材料的多尺度显微镜
DOI：
10.1016/j.nme.2022.101285
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发表时间：
2022
影响因子：
2.6
通讯作者：
Marshall J
中科院分区：
文献类型：
--
作者：
Marshall J
在展示球形托卡马克的实用性时，保护超导磁体免受中子辐射至关重要。反应性烧结硼化物（RSB）是有前途的辐射密集材料和优秀的慢（<10 keV）中子衰减器。目前还没有关于 RSB 的实验辐射数据，因此在研究主动聚变环境中 RSB 的辐射响应和老化之前，需要建立 RSB 微观结构的基线。这项工作研究了超过 5 个数量级的 RSB 材料的结构和成分。使用 SEM、TEM-EDX、原子探针断层扫描 (APT) 和 XRD 评估了精选 RSB 组合物的微观结构。据观察，烧结 RSB 的主要成分是 FeWB/FeW2B2 体、混合硼化钨和 WC，作为存在的关键硬质相。 TEM 和 SEM 检测到一种复杂的富铁合金，具有接近纯的 Fe 间隙相。这项工作的主要发现是：(i) 在考虑微观结构和相存在时，碳平衡与硼含量一样重要；(ii) FeWB/FeW2B2 的生长高度依赖于温度；(iii) 致密、连贯的 RSB 形成取决于总硼和碳原子百分比 (B + C)at% 为 40 % < x ≤ 50 %。
Protecting superconducting magnets from neutron irradiation is critically important when demonstrating the utility of spherical tokamaks. Reactive Sintered Borides (RSBs) are promising radiation-dense materials and excellent attenuators of slow (<10 keV) neutrons. No experimental radiation data yet exists on RSBs, hence the need to establish a baseline of RSB microstructure prior to studies on radiation response and aging of RSBs in an active fusion environment.This work investigates the structure and composition of RSB materials over 5 orders of magnitude. SEM, TEM-EDX, atom probe tomography (APT) and XRD were evaluated the microstructure of a selection of RSB compositions. Sintered RSBs were observed to be dominated by FeWB/FeW2B2 bodies, mixed tungsten borides and WC as the key hard phases present. TEM and SEM detected a complex Fe-rich alloy with near-pure Fe interstitial phases. Key findings from this work are that (i) carbon balance is as significant as boron content when considering microstructure and phase presence;(ii) FeWB/FeW2B2 growth is highly temperature dependant and (iii) dense, coherent RSB formation is contingent on the total boron and carbon atomic percentage (B + C)at% is 40 % < x ≤ 50 %.