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Deformation and Failure Mechanisms of Thermoelectric Type-I Clathrate Ba8Au6Ge40
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2022-01-12 , DOI: 10.1021/acsami.1c22730 Xiaolian Zhang 1 , Pengcheng Zhai 1, 2 , Xiege Huang 1 , Sergey I Morozov 3 , Bo Duan 1 , Wenjuan Li 1 , Gang Chen 1 , Guodong Li 1, 2 , William A Goddard 4
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2022-01-12 , DOI: 10.1021/acsami.1c22730 Xiaolian Zhang 1 , Pengcheng Zhai 1, 2 , Xiege Huang 1 , Sergey I Morozov 3 , Bo Duan 1 , Wenjuan Li 1 , Gang Chen 1 , Guodong Li 1, 2 , William A Goddard 4
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Type-I clathrate Ba8Au6Ge40, possessing an interesting structure stacked by polyhedrons, is a potential “phonon-glass, electron-crystal” thermoelectric material. However, the mechanical properties of Ba8Au6Ge40 vital for industrial applications have not been clarified. Here, we report the first density functional theory calculations of the intrinsic mechanical properties of thermoelectric clathrate Ba8Au6Ge40. Among the different loading directions, the {110}/⟨001⟩ shearing and ⟨110⟩ tension are the weakest, with strengths of 4.51 and 6.64 GPa, respectively. Under {110}/⟨001⟩ shearing, the Ge–Ge bonds undergo significant stretching and twisting, leading to a severe distortion of the tetrakaidecahedral cage, giving rise to the fast softening of the flank Au–Ge bonds. At a strain of 0.2655, the Au–Ge bonds suddenly break, resulting in the collapse of the cage and the failure of the material. Under a ⟨110⟩ tension, the stretching of the Ge–Ge bonds keeps accelerating the softening of the Au–Ge bonds in the top/bottom hexagons, which releases the stress and disables the structure. The Au–Ge bonds are more rigid, contributing two-thirds of the structural deformation resistance. This work provides a new insight to understand the failure mechanisms of type-I clathrates with varied framework constitutions, which should help inform the design of robust thermoelectric clathrate materials.
中文翻译：
热电I型包合物Ba8Au6Ge40的变形和失效机理
I型包合物Ba 8 Au 6 Ge 40具有有趣的多面体堆叠结构，是一种潜在的“声子玻璃、电子晶体”热电材料。然而，对于工业应用至关重要的 Ba 8 Au 6 Ge 40的机械性能尚未阐明。在这里，我们报告了热电包合物 Ba 8 Au 6 Ge 40的固有力学性能的第一次密度泛函理论计算。. 在不同的加载方向中，{110}/⟨001⟩剪切和⟨110⟩张力最弱，强度分别为4.51和6.64 GPa。在{110}/⟨001⟩剪切作用下，Ge-Ge键发生明显的拉伸和扭曲，导致十四面体笼的严重变形，导致侧翼Au-Ge键快速软化。在 0.2655 的应变下，Au-Ge 键突然断裂，导致笼子坍塌和材料失效。在⟨110⟩张力下，Ge-Ge键的拉伸不断加速顶部/底部六边形中Au-Ge键的软化，从而释放应力并使结构失效。Au-Ge 键更坚硬，贡献了三分之二的结构变形阻力。
更新日期：2022-01-26
中文翻译：
热电I型包合物Ba8Au6Ge40的变形和失效机理
I型包合物Ba 8 Au 6 Ge 40具有有趣的多面体堆叠结构，是一种潜在的“声子玻璃、电子晶体”热电材料。然而，对于工业应用至关重要的 Ba 8 Au 6 Ge 40的机械性能尚未阐明。在这里，我们报告了热电包合物 Ba 8 Au 6 Ge 40的固有力学性能的第一次密度泛函理论计算。. 在不同的加载方向中，{110}/⟨001⟩剪切和⟨110⟩张力最弱，强度分别为4.51和6.64 GPa。在{110}/⟨001⟩剪切作用下，Ge-Ge键发生明显的拉伸和扭曲，导致十四面体笼的严重变形，导致侧翼Au-Ge键快速软化。在 0.2655 的应变下，Au-Ge 键突然断裂，导致笼子坍塌和材料失效。在⟨110⟩张力下，Ge-Ge键的拉伸不断加速顶部/底部六边形中Au-Ge键的软化，从而释放应力并使结构失效。Au-Ge 键更坚硬，贡献了三分之二的结构变形阻力。
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