Precipitation of binary quasicrystals along dislocations
Zhiqing Yang1,2, Lifeng Zhang3, Matthew F Chisholm4
1Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, School of Materials Science and Engineering, University of Science and Technology of China, Shenyang, 110016, China. yangzq@imr.ac.cn.
Nature Communications
|February 25, 2018
Summary
Researchers discovered quasicrystalline precipitates forming along dislocations in Mg-Zn alloys. These precipitates, with random-tiling structures, may influence alloy strength and dislocation movement.
Area of Science:
- Materials Science
- Crystallography
- Metallurgy
Background:
- Dislocations in crystals break bulk symmetry, creating local fivefold ring structures.
- Typically, dislocations do not form aperiodic structures along their length.
Purpose of the Study:
- To investigate the formation of aperiodic structures at dislocation cores.
- To characterize the nature of precipitates formed in Mg-Zn alloys.
Main Methods:
- Atomic resolution observations of Mg-Zn alloys.
- Analysis of dislocation core structures and precipitate formation.
Main Results:
- Formation of extended binary quasicrystalline precipitates with Penrose-like random-tiling structures.
- Icosahedral chains of Zn interstitial atoms templated by fivefold rings at dislocation cores.
- Precipitates composed of rhombic and hexagonal tiles parallel to dislocation lines.
Conclusions:
- Dislocation cores can nucleate aperiodic quasicrystalline structures.
- The observed precipitation impacts dislocation glide and potentially alloy strength.
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