Mechanisms of Failure in Nanoscale Metallic Glass

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• 作者：X. Wendy Gu ; Mehdi Jafary-Zadeh ; David Z. Chen ; Zhaoxuan Wu ; Yong-Wei Zhang ; David J. Srolovitz ; Julia R. Greer
• 刊名：Nano Letters
• 出版年：2014
• 出版时间：October 8, 2014
• 年：2014
• 卷：14
• 期：10
• 页码：5858-5864
• 全文大小：443K
• ISSN：1530-6992

文摘

The emergence of size-dependent mechanical strength in nanosized materials is now well-established, but no fundamental understanding of fracture toughness or flaw sensitivity in nanostructures exists. We report the fabrication and in situ fracture testing of 鈭?0 nm diameter Ni鈥揚 metallic glass samples with a structural flaw. Failure occurs at the structural flaw in all cases, and the failure strength of flawed samples was reduced by 40% compared to unflawed samples. We explore deformation and failure mechanisms in a similar nanometallic glass via molecular dynamics simulations, which corroborate sensitivity to flaws and reveal that the structural flaw shifts the failure mechanism from shear banding to cavitation. We find that failure strength and deformation in amorphous nanosolids depend critically on the presence of flaws.

Keywords:

Size effect; metallic glass; notch sensitivity; flaw sensitivity; mechanical properties; fracture; molecular dynamics