纳米力学测试Journal Club
We regularly come across interesting and informative materials research articles. Members of our Nanomechanical Testing Journal Club receive brief reviews of select papers and direct links to the full article. Our Journal Club is meant to be a helpful tool that keeps you up-to-date on the newest in Nanomechanical Testing research and to assist you in discovering articles you may have missed.
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Highly Ductile Amorphous Oxide at Room Temperature and High Strain Rate
氧化物眼镜是现代世界不可或缺的一部分，但是它们的实用性可以受到室温下的特征性脆性的限制。我们表明，无定形氧化铝可以在室温下永久变形而不会通过粘性蠕变机构在高应变速率下骨折。这些薄膜可以在室温下达到流动应力，并且只要材料密集并且没有几何缺陷，就可以塑料流动至100％的总伸长率。我们的研究表明，低温下无定形氧化物的延展性要高于以前的观察结果。这一发现可能有助于实现以新方式促进损害的玻璃材料，并有可能提高应用程序和电池等应用的机械阻力和可靠性。必威手机客户端
埃尔卡·J·弗兰克伯格（Erkka J.Matteo Vanazzi，Lucian Roiban，Jaakko Akola，Fabio di Fonzo，ErkkiLevänen，Karine Masenelli-Varlot
Science，2019，366（6467），864-69
DOI: 10.10.1126/science.aav1254
High-Throughput Nanoindentation for Statistical and Spatial Property Determination
与几乎所有其他机械测试（例如张力或压缩）相比，标准的纳米引导测试是“高通量”。但是，每小时数十个测试的典型速率可以显着提高。这些较高的测试率使原本不切实际的研究需要数千个凹痕，例如高分辨率性能映射和详细的统计研究。但是，必须注意避免测量中的系统错误，包括选择压痕深度/间距，以避免塑料区域的重叠，堆积和相邻的微结构特征在所测试的材料中的影响。此外，由于需要快速加载速率，还必须考虑应变率灵敏度。对这些效果进行了审查，重点放在进行免费的标准纳米识别测量以解决这些问题上。该技术的实验应用，包括焊缝的映射，微结构和具有不同长度尺度的复合材料，以及研究表面粗糙度对名义均匀标本的影响。
Eric Hintsala, Ude Hangen, Douglas D. Stauffer
材料杂志必威手机客户端, 2018, 70 (4), 494-503
DOI: 10.1007/s11837-018-2752-0
Bioinspired Nacre-like Alumina with a Bulk-metallic Glass-forming Alloy as a Compliant Phase
Bioinspired ceramics with micron-scale ceramic “bricks” bonded by a metallic “mortar” are projected to result in higher strength and toughness ceramics, but their processing is challenging as metals do not typically wet ceramics. To resolve this issue, we made alumina structures using rapid pressureless infiltration of a zirconium-based bulk-metallic glass mortar that reactively wets the surface of freeze-cast alumina preforms. The mechanical properties of the resulting Al2O3with a glass-forming compliant-phase change with infiltration temperature and ceramic content, leading to a trade-off between flexural strength (varying from 89 to 800 MPa) and fracture toughness (varying from 4 to more than 9 MPa·m½). The high toughness levels are attributed to brick pull-out and crack deflection along the ceramic/metal interfaces. Since these mechanisms are enabled by interfacial failure rather than failure within the metallic mortar, the potential for optimizing these bioinspired materials for damage tolerance has still not been fully realized.
Amy Wat, Je In Lee, Chae Woo Ryu, Bernd Gludovatz, Jinyeon Kim, Antoni P. Tomsia, Takehiko Ishikawa, Julianna Schmitz, Andreas Meyer, Markus Alfreider, Daniel Kiener, Eun Soo Park, Robert O'Ritchie
Nature Communications, 2019, 10 (961)
DOI: 10.1038/s41467-008753-6
In SituTEM Observation of Rebonding on Fractured Silicon Carbide
BioSilicon carbide (SiC) is widely used in harsh environments and under extreme conditions, including at high-power, high-temperature, high-current, high-voltage and high-frequency. The rebonding and self-matching of stack faults (SFs) is highly desirable to avoid catastrophic failure for SiC devices, especially for specific applications in the aerospace and nuclear power industries. In this study, a novel approach was developed using an eyebrow hair to pick up and transfer nanowires (NWs), in order to obtain原位transmission electron microscope (TEM) images of the rebonding and self-matching of SFs at atomic resolution. During rebonding and healing, the electron beam was shut off. Rebonding on the fractured surfaces of monocrystalline and amorphous SiC NWs was observed by原位TEM at room temperature. The fracture strength was 1.7 GPa after crack-healing, restoring 12.9% of that of a single crystal NW. Partial recrystallization along the <111> orientation and the self-matching of SFs are responsible for the rebonding of the monocrystalline NW. In comparison, the fracture strengths were 6.7 and 5.5 GPa for the first and second rebonding, respectively recovering 67% and 55% of that of an amorphous NW. Atomic diffusion contributed enormously to the rebonding on fractured surfaces of an amorphous NW, resulting in a healed surface consisting of an amorphous phase and crystallites. This rebonding function provides new insight into the fabrication of high-performance SiC devices for the aerospace, optoelectronic and semiconductor industries.
Zhenyu Zhang, Junfeng Cui, Bo Wang, Haiyue Jiang, Guoxin Chen, Jinhong Yu, Chengte Lin, Chun Tang, Alexander Hartmaier, Junjie Zhang, Jun Luo, Andreas Rosenkranz, Nan Jiang, Dongming, Guo
纳米级, 2018, 10, 6261-69
DOI: 10.10.1039/C8NR00341F
