Zhang Xuejiao, Wang Jing, Yang Zhenyu, Tang Xuke, Yue Yonghai
School of Chemistry, Beihang University, Beijing, 100191, People's Republic of China.
Institute of Solid Mechanics, Beihang University, Beijing, 100191, People's Republic of China.
Sci Rep. 2020 Jul 9;10(1):11386. doi: 10.1038/s41598-020-67652-9.
Materials' mechanical properties highly depend on their internal structures. Designing novel structure is an effective route to improve materials' performance. One-dimensional disordered (ODD) structure is a kind of particular structure in silicon carbide (SiC), which highly affects its mechanical properties. Herein, we show that SiC nanowires (NWs) containing ODD structure (with an occupation ratio of 32.6%) exhibit ultrahigh tensile strength and elastic strain, which are up to 13.7 GPa and 12% respectively, approaching the ideal theoretical limit. The ODD structural occupation ratio effect on mechanical properties of SiC NWs has been systematically studied and a saddle shaped tendency for the strength versus occupation ratio is firstly revealed. The strength increases with the increase of the ODD occupation ratio but decreases when the occupation ratio exceeds a critical value of ~ 32.6%, micro twins appear in the ODD region when the ODD segment increases and soften the ODD segment, finally results in a decrease of the strength.
材料的力学性能高度依赖于其内部结构。设计新颖的结构是提高材料性能的有效途径。一维无序（ODD）结构是碳化硅（SiC）中的一种特殊结构，它对其力学性能有很大影响。在此，我们表明，含有ODD结构（占有率为32.6%）的SiC纳米线（NWs）表现出超高的拉伸强度和弹性应变，分别高达13.7 GPa和12%，接近理想理论极限。系统研究了ODD结构占有率对SiC NWs力学性能的影响，并首次揭示了强度与占有率之间的鞍形趋势。强度随着ODD占有率的增加而增加，但当占有率超过临界值~32.6%时强度降低，当ODD段增加时，ODD区域会出现微孪晶，使ODD段软化，最终导致强度下降。
