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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Transformation-Mediated Kinetic Unfreezing in Mixed-Motif Amorphous Carbon
Kang Wang1, ZhongTing Zhang1, YinBo Zhu1
1State Key Laboratory of Nonlinear Mechanics, Department of Modern Mechanics, University of Science and Technology of China, Hefei230027, China.
ACS Nano
|July 20, 2026
Summary
Mixed-motif amorphous carbon softens via transformation-mediated kinetic unfreezing. Microstructural changes in amorphous diaphite (a-DG) activate atomic mobility, differing from conventional amorphous solids.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Computational Chemistry
Background:
- High-temperature softening limits amorphous solid reliability.
- Mixed-motif amorphous carbon (e.g., amorphous diaphite) has coexisting sp2 and sp3 phases.
- Understanding microstructural effects on softening is crucial for extreme applications.
Purpose of the Study:
- To elucidate how microstructural motifs govern high-temperature softening in amorphous carbon.
- To investigate the transformation-mediated kinetic unfreezing mechanism.
- To provide a structural basis for enhancing the high-temperature performance of advanced carbon materials.
Main Methods:
- Large-scale molecular dynamics simulations.
- Kinetic statistical analyses.
- Studied amorphous diaphite (a-DG) with disordered multilayer graphene (DMG) and continuous random network (CRN) structures.
Main Results:
- Revealed a transformation-mediated kinetic unfreezing process driven by dynamical mismatch between sp2/sp3 motifs.
- Observed graphitization and connectivity reconstruction facilitated by stress mismatch.
- Demonstrated that the DMG matrix provides mobility while the CRN skeleton graphitizes, releasing constraints and activating global atomic mobility.
Conclusions:
- Mixed-motif amorphous carbon exhibits a unique kinetic unfreezing scenario distinct from conventional amorphous solids.
- Microstructural transformation, not just preserved topology, drives softening.
- Identified mixed-motif amorphous carbon as a platform for tailoring high-temperature material properties.
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