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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
Melting and glass transition for Ni clusters
Yuyong Teng1, Xianghua Zeng, Haiyan Zhang
1College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, China.
The Journal of Physical Chemistry. B
|February 13, 2007
Summary
Molecular dynamics simulations reveal nickel cluster melting points depend on size and symmetry. Higher symmetry leads to higher melting temperatures, with latent heat significantly influencing this relationship.
Area of Science:
- Materials Science
- Computational Chemistry
- Condensed Matter Physics
Background:
- Understanding the thermodynamic properties of metallic clusters is crucial for materials science.
- Nanoparticle behavior deviates significantly from bulk materials, necessitating specific investigation.
- Melting phenomena in small systems are complex and influenced by surface and size effects.
Purpose of the Study:
- To investigate the melting behavior of nickel (Ni) clusters of varying sizes (N = 29, 50-150).
- To explore the influence of cluster size and structural symmetry on melting temperatures.
- To determine the specific heat and latent heat of fusion for nickel clusters.
Main Methods:
- Molecular dynamics (MD) simulations were employed.
- A quantum-corrected Sutton-Chen (Q-SC) many-body potential was utilized for accurate interatomic interactions.
- Caloric curves were analyzed to determine melting points and specific heats.
Main Results:
- Different melting behaviors were observed: surface melting for Ni147, direct melting for Ni79, and glass transition for Ni29.
- Melting points were found to be size-dependent and influenced by cluster symmetry; higher symmetry correlated with higher melting points (540 K for Ni147, 680 K for Ni79, 940 K for Ni29).
- Specific heats were calculated as 4.1 kB/atom for liquid and 3.1 kB/atom for solid phases, largely independent of size, and the latent heat of fusion was identified as a dominant factor in melting temperatures.
Conclusions:
- Nickel cluster melting is governed by both size and structural symmetry.
- The latent heat of fusion plays a critical role in determining melting temperatures.
- MD simulations with the Q-SC potential provide accurate insights into the melting dynamics of metallic clusters.
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