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- Ahuja, R., et al.
(författare)
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Electronic structure of Ti3SiC2
- 2000
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 76:16, s. 2226-2228
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Tidskriftsartikel (refereegranskat)
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| 8. |
- Belonoshko, Anatoly B., et al.
(författare)
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Mechanism for the kappa-Al2O3 to the alpha-Al2O3 transition and the stability of kappa-Al2O3 under volume expansion
- 2000
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 61:5, s. 3131-3134
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Tidskriftsartikel (refereegranskat)abstract
- The kappa-Al2O3 metastable phase is an important material for producing cutting tools. However, at temperatures above 1000 K the kappa phase transforms into the stable modification alpha-Al2O3. We have investigated mechanisms for this transformation by means of molecular dynamic simulations using pair potentials. We have found that for the temperature range above 1000 K the mean square displacement of the atoms at the free surface changes its behavior drastically. Since, as was calculated, all other possible driving mechanisms of the phase transition such as pressure and/or temperature without a free surface are not sufficient to cause the transition, the free surface is the major factor initiating the unwanted transition. To hinder the transition one has to slow down the diffusion at the free surface. As an alternative to chemical vapor deposition of thin films of kappa-Al2O3 phase at surfaces of cutting tools, it is found that it is thermodynamically possible to obtain kappa-Al2O3 in a stable phase at a volume expansion of the alpha-Al2O3 phase at a negative pressure of about - 40 kbar.
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| 9. |
- Belonoshko, Anatoly B., et al.
(författare)
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Molecular dynamics of LiF melting
- 2000
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 61:18, s. 11928-11935
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Tidskriftsartikel (refereegranskat)abstract
- We performed molecular-dynamics simulations of the melting and/or freezing of LiF. The simulations were done using the Tosi-Fumi model and our own model of interatomic interactions. The latter was verified by ab initio calculations of the equation of state for LiF. We show that the recent molecular-dynamics calculations by Boehler and co-workers are not adequate and their model for the interactions is not capable of providing melting temperatures in agreement with experiment. Our calculated pressure dependence of the melting temperatures gives valuable information. We found that the B1-B2 transition in LiF at around 1 Mbar removes the discrepancy between the diamond-anvil cell and shockwave melting temperatures. An explanation of the controversy between low and high melting temperatures obtained from diamond-anvil cell experiments is suggested.
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| 10. |
- Belonoshko, Anatoly B., et al.
(författare)
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Quasi ab initio molecular dynamic study of Cu melting
- 2000
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 61:6, s. 3838-3844
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the melting of Cu theoretically by means of a molecular dynamic method employing the Sutton-Chen model for the interatomic interaction. This interaction has been fitted to reproduce results from first-principles self-consistent total-energy calculations within the local-density approximation using the full-potential linear-muffin-tin-orbital method for the bcc, fee, hcp, and liquid configurations. No experimental data were used to tune the potential. A large number of properties including equation of state, melting temperature, high-pressure melting curve, change of volume and entropy at melting, liquid structure, diffusion coefficient in liquid, and vacancy formation energy are all in good agreement with experimental data. Inclusion of the full potential energy of a liquid configuration in the fitting procedure is critical for obtaining good agreement with experiment. Different ways to calculate the melting transition are shown to produce very different results. The use of a large number of particles in combination with the solid-liquid interface as an initial configuration in the simulation is essential in order to obtain the correct melting temperatures.
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