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Inverse pseudo Hall-Petch relation in polycrystalline graphene
1International Center for Applied Mechanics, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an 710049, China.
Scientific Reports
|August 9, 2014
Summary
Polycrystalline graphene exhibits brittle failure, with cracks initiating at grain boundaries. Its strength is inversely related to grain size, following a pseudo Hall-Petch relationship, crucial for device applications.
Area of Science:
- Materials Science
- Nanotechnology
- Solid Mechanics
Background:
- Graphene's unique properties make it promising for advanced applications.
- Understanding the mechanical behavior of polycrystalline graphene is key to its practical use.
- Grain size significantly influences material properties.
Purpose of the Study:
- To investigate the failure mechanisms of polycrystalline graphene.
- To analyze the relationship between grain size and mechanical strength.
- To provide insights for optimizing graphene-based devices.
Main Methods:
- Molecular dynamics simulations were employed.
- Polycrystalline graphene models with varying grain sizes and distributions were simulated.
- Failure behavior under stress was analyzed.
Main Results:
- Polycrystalline graphene demonstrates brittle failure.
- Grain boundary junctions act as primary sites for crack initiation.
- A pseudo Hall-Petch relationship was observed between breaking strength and average grain size.
- The weakest-link model effectively explains the observed failure behavior.
Conclusions:
- The study elucidates the brittle failure mode of polycrystalline graphene.
- Findings support the weakest-link model for predicting material strength.
- Results offer guidance for tailoring mechanical properties of graphene for flexible electronics and nano-electromechanical systems.
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