Neutron shielding materials face imbalanced behaviors among shielding, strength, and ductility properties. Based on the requirement of the high property shielding particles, a superior semi-coherent τ(AlMgGd) phase was designed and predicted by cluster expansion (CE) method using density functional theory calculations. To realize its shielding property, the Powder Metallurgy-based routines (i.e., powder fabrication, spark plasma sintering, and hot extrusion techniques) are used to fabricate 6TiB/Al-6Mg-5Gd (wt.%) composite with dispersed refined τ phases and homogenized TiB distribution. The atomic structure of ternary phase τ is examined by aberration-corrected high-angle annual dark-field (HAADF) scanning transmission electron microscope (STEM) and energy dispersive X-ray spectroscopy (EDXS) STEM experiments, which is well complied with the calculated compound (AlMgGd). In detail, the τ(AlMgGd) phase has a semi-coherent interface both with α-Al and TiB, which is consistent with the prediction of interface relationships. With the optimized interfaces, the TiB and τ phases can effectively promote recrystallization and suppress grain growth, leading to the formation of ultra-fine grain structure. Then, the composite exhibits advanced shielding properties (Macroscopic transmission cross section ∼24.1 /cm, higher than 30 %BC/Al) and optimized synergic mechanical properties (Ultimate tensile strength ∼506 MPa, elongation ∼12.9 %), which are far higher than available Al-based neutron shielding materials. Finally, the underlying strength-ductility mechanisms are discussed. Critically, the design and optimization of shielding particle interfaces are reliable strategies for developing novel structural-functional integrated materials.

中文翻译：

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多半共格粒子强化超细晶铝复合材料用于中子屏蔽材料


中子屏蔽材料面临着屏蔽、强度和延展性之间的不平衡行为。基于高性能屏蔽粒子的要求，采用密度泛函理论计算的团簇膨胀（CE）方法设计并预测了优异的半共格τ（AlMgGd）相。为了实现其屏蔽性能，采用基于粉末冶金的工艺（即粉末制造、放电等离子烧结和热挤压技术）来制造具有分散细化 τ 相和TiB 分布均匀。通过像差校正高角度年度暗场（HAADF）扫描透射电子显微镜（STEM）和能量色散X射线光谱（EDXS）STEM实验检查了三元相τ的原子结构，结果与计算结果吻合良好化合物（AlMgGd）。具体来说，τ(AlMgGd)相与α-Al和TiB均具有半共格界面，这与界面关系的预测一致。通过优化的界面，TiB和τ相可以有效促进再结晶并抑制晶粒长大，从而形成超细晶粒结构。然后，该复合材料表现出先进的屏蔽性能（宏观传输截面∼24.1 /cm，高于30%BC/Al）和优化的协同机械性能（极限拉伸强度∼506 MPa，伸长率∼12.9%），远高于可用铝基中子屏蔽材料。最后，讨论了潜在的强度-延展性机制。至关重要的是，屏蔽颗粒界面的设计和优化是开发新型结构功能集成材料的可靠策略。