论文名称：Ultrahigh Recovery of Fracture Strength on Mismatched Fractured Amorphous Surfaces of Silicon Carbide
论文类型：期刊论文
发表刊物：ACS NANO
收录刊物：SCIE、PubMed
卷号：13
期号：7
页面范围：7483-7492
ISSN号：1936-0851
关键字：fracture strength; in situ TEM; nanomechanical test; molecular dynamics; SiC
摘要：Nanowires (NWs) have been envisioned as building blocks of nanotechnology and nanodevices. In this study, NWs were manipulated using a weasel hair and fixed by conductive silver epoxy, eliminating the contaminations and damages induced by conventional beam depositions. The fracture strength of the amorphous silicon carbide was found to be 8.8 GPa, which was measured by in situ transmission electron microscopy nanomechanical testing, approaching the theoretical fracture limit. Here, we report that self-healing of mismatched fractured amorphous surfaces of brittle NWs was discovered. The fracture strength was found to be 5.6 GPa on the mismatched fractured surfaces, recovering 63.6% of that of pristine NWs. This is an ultrahigh recovery, due to the limits of reconstruction of dangling bonds on the fractured amorphous surfaces and the mismatched areas. Simulation by molecular dynamics showed fracture strength recovery of 65.9% on the mismatched fractured amorphous surfaces, which is in good agreement with the experimental results. Healing on the mismatched fractured amorphous surfaces is by reorganization of Si-C bonds forming Si-C and Si Si bonds. The potential energy increases 2.6 eV in the reorganized Si-C bonds and decreases by 3.2 and 1.9 eV, respectively, in the formed Si-C and Si Si bonds. These findings provide insights for the reliability, design, and fabrication of high performance NW-based devices, to avoid catastrophic failure working in harsh and extreme environments.
发表时间：2019-07-01