Jianping Lai, Mengli Liu, An Zhang, Amit Datye, Udo D Schwarz, Fan Zhao, Fei Zhao, Jiaxin Yu
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引用次数: 0
Abstract
Although the enhanced structural relaxation is usually believed to be an important contributor to work hardening of metallic glasses subjected to triaxial stress state, an direct observation of relaxation process in response to work hardening has not been achieved in metallic glasses. Here we show that by nanoscratching on an atomically flat bulk metallic glass surface, the small atomic force microscopy tip with a radius of ≈ 10 nm brings about a large hydrostatic stress within stressed volume, which enables a densifying plastic flow via enhanced structural relaxation and leads to the work hardening behavior, as evidenced by an obvious decrease in friction force signals within scratched regions. Further examination on the atomic structure beneath the scratched surface using high resolution transmission electron microscopy reveals a relaxed structural configuration, which is indicated by disperse clusters of medium-range order scale in the case of line scratching and nucleated nanocrystals in the case of cyclic scratching. This study provides a compelling evidence for stress-driven structural relaxation, greatly deepening the understanding of work hardening mechanism in metallic glasses.
期刊介绍:
Friction is a peer-reviewed international journal for the publication of theoretical and experimental research works related to the friction, lubrication and wear. Original, high quality research papers and review articles on all aspects of tribology are welcome, including, but are not limited to, a variety of topics, such as:
Friction: Origin of friction, Friction theories, New phenomena of friction, Nano-friction, Ultra-low friction, Molecular friction, Ultra-high friction, Friction at high speed, Friction at high temperature or low temperature, Friction at solid/liquid interfaces, Bio-friction, Adhesion, etc.
Lubrication: Superlubricity, Green lubricants, Nano-lubrication, Boundary lubrication, Thin film lubrication, Elastohydrodynamic lubrication, Mixed lubrication, New lubricants, New additives, Gas lubrication, Solid lubrication, etc.
Wear: Wear materials, Wear mechanism, Wear models, Wear in severe conditions, Wear measurement, Wear monitoring, etc.
Surface Engineering: Surface texturing, Molecular films, Surface coatings, Surface modification, Bionic surfaces, etc.
Basic Sciences: Tribology system, Principles of tribology, Thermodynamics of tribo-systems, Micro-fluidics, Thermal stability of tribo-systems, etc.
Friction is an open access journal. It is published quarterly by Tsinghua University Press and Springer, and sponsored by the State Key Laboratory of Tribology (TsinghuaUniversity) and the Tribology Institute of Chinese Mechanical Engineering Society.