当前位置：
X-MOL 学术
›
J. Phys. Chem. C
›
论文详情
Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
Improved Ductility of Boron Carbide by Microalloying with Boron Suboxide
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2015-10-21 00:00:00 , DOI: 10.1021/acs.jpcc.5b08086 Bin Tang 1, 2 , Qi An 2 , William A. Goddard 2
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2015-10-21 00:00:00 , DOI: 10.1021/acs.jpcc.5b08086 Bin Tang 1, 2 , Qi An 2 , William A. Goddard 2
Affiliation
|
Boron carbide (B4C) is the third hardest material in nature, but applications are hindered by its brittle failure under impact. We found that this brittle failure of B4C arises from amorphous shear band formation due to deconstruction of icosahedral clusters, and on the basis of this model we suggest and validate with quantum mechanics (QM, PBE flavor of density function theory) that a laminated B4C–B6O composite structure will eliminate this brittle failure. Using QM to apply shear deformations along various slip systems, we find that the (001)/[100] slip system has the lowest maximum shear strength, indicating it to be the most plausible slip system. We find that this composite structure has a shear strength of 38.33 GPa, essentially the same as that of B4C (38.97 GPa), indicating the same intrinsic hardness as B4C. However, the critical failure strain for (001)/[100] slip in the composite is 0.465, which is 41% higher than B4C, indicating a dramatically improvement on ductility. This arises because incorporation of B6O prevents the failure mechanism of B4C in which the carbene formed during shear deformation reacts with the C–B–C chains. This suggests a new strategy for designing ductile superhard ceramics.
中文翻译：
通过过氧化硼微合金化改善碳化硼的延展性
碳化硼（B 4 C）是自然界中第三高硬度的材料，但由于其在冲击下的脆性破坏而阻碍了其应用。我们发现B 4 C的这种脆性破坏是由于二十面体簇解构而形成的无定形剪切带所致，并且在此模型的基础上，我们建议并验证了量子力学（QM，密度泛函理论的PBE风味） B 4 C–B 6O型复合结构将消除这种脆性破坏。使用QM沿各种滑移系统施加剪切变形，我们发现（001）/ [100]滑移系统具有最低的最大抗剪强度，表明它是最合理的滑移系统。我们发现该复合结构的剪切强度为38.33 GPa，与B 4 C（38.97 GPa）基本相同，表明其固有硬度与B 4 C相同。但是，（001）/ [复合材料中的100]滑移为0.465，比B 4 C高41％，表明延展性显着提高。这是因为掺入B 6 O阻止了B 4的失效机理。碳在剪切变形过程中形成的卡宾与C–B–C链反应。这提出了设计延性超硬陶瓷的新策略。
更新日期：2015-10-21
中文翻译：
通过过氧化硼微合金化改善碳化硼的延展性
碳化硼（B 4 C）是自然界中第三高硬度的材料，但由于其在冲击下的脆性破坏而阻碍了其应用。我们发现B 4 C的这种脆性破坏是由于二十面体簇解构而形成的无定形剪切带所致，并且在此模型的基础上，我们建议并验证了量子力学（QM，密度泛函理论的PBE风味） B 4 C–B 6O型复合结构将消除这种脆性破坏。使用QM沿各种滑移系统施加剪切变形，我们发现（001）/ [100]滑移系统具有最低的最大抗剪强度，表明它是最合理的滑移系统。我们发现该复合结构的剪切强度为38.33 GPa，与B 4 C（38.97 GPa）基本相同，表明其固有硬度与B 4 C相同。但是，（001）/ [复合材料中的100]滑移为0.465，比B 4 C高41％，表明延展性显着提高。这是因为掺入B 6 O阻止了B 4的失效机理。碳在剪切变形过程中形成的卡宾与C–B–C链反应。这提出了设计延性超硬陶瓷的新策略。
京公网安备 11010802027423号