DFT study on the adsorption and absorption behaviors of liquid nitrogen in the Mg nano alloys synthesized from powder metallurgy
| Autor: | Chang-Soo Kim, Marjan Nezafati, Joon-Sang Park, J. B. Ferguson, Il Sohn, Kyu Cho |
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| Rok vydání: | 2015 |
| Předmět: |
Materials science
Nanocomposite General Computer Science Metallurgy Lattice diffusion coefficient General Physics and Astronomy chemistry.chemical_element General Chemistry Liquid nitrogen Nitrogen Computational Mathematics Adsorption Chemical engineering chemistry Mechanics of Materials Powder metallurgy Nano Molecule General Materials Science |
| Zdroj: | Computational Materials Science. 105:18-26 |
| ISSN: | 0927-0256 |
| Popis: | Mg-based metal-matrix nanocomposites (MMNCs) are lauded as one of the most promising structural materials for vehicle, military, and construction applications. These Mg MMNCs are often synthesized using the powder metallurgy (PM) process under liquid nitrogen cryogenic environments to control the grain sizes. It is believed that proper incorporation of the nitrogen species into the bulk lattice during processing could strongly enhance the mechanical properties of MMNCs by forming N-rich dispersoids. In this work, using the density-functional theory (DFT), we have studied the adsorption and absorption phenomena of liquid nitrogen molecule/atoms that can be applied to the Mg MMNC PM processing. The study includes the impacts of binding sites, alloying elements (Al, Zn, and Y), and surface crystallographic planes on the nitrogen molecule adsorption energies. We also examined the transition state (TS) behaviors for the bond breaking and lattice diffusion of nitrogen. The results show that ∼1.13 eV would be required for nitrogen molecule to break the triple bonding and to diffuse into the Mg bulk lattice. Also, it was found that addition of Y can greatly enhance the binding strength of N 2 molecule on the Mg surface. |
| Databáze: | OpenAIRE |
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