Quantized grain boundary states controls nanoparticle coalescence during crystallization
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
First order transitions like crystallization are ubiquitous in nature. Yet, mechanistic details of crystallization, i.e. polymorph selection during nucleation, details of particle aggregation, role of pre-alignment during aggregation, remain unclear. At variance with the commonly invoked oriented attachment hypothesis, we show many nanoparticles with different misorientations coalesce to form single crystals. The alignment of nanoparticles after contact irrespective of their initial misorientation is driven by extensive dislocation activity at the interface leading to disintegration of grain boundaries that is followed by surface diffusion aided neck growth and densification. Grain boundaries disintegrate because the classical Read-Shockley description breaks down at the nanoscale and only few discrete energy levels are allowed. This points to a revision of the scope of oriented attachment in crystal growth, and the role of grain boundaries during deformation and grain growth in nanocrystalline materials.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- DOE Contract Number:
- AC52-07NA27344
- OSTI ID:
- 1463823
- Report Number(s):
- LLNL-JRNL-740271; 894407
- Journal Information:
- Proposed Journal Article, unpublished, Vol. 2017; ISSN 9999-9999
- Publisher:
- See Research Organization
- Country of Publication:
- United States
- Language:
- English
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