%0 Journal Article %1 0295-5075-73-5-719 %A Ravi, C. %A Wolverton, C. %A Ozoliņš, V. %D 2006 %J EPL (Europhysics Letters) %K ab initio meta-stable phase thermodynamics %N 5 %P 719 %T Predicting metastable phase boundaries in Al–Cu alloys from first-principles calculations of free energies: The role of atomic vibrations %U http://stacks.iop.org/0295-5075/73/i=5/a=719 %V 73 %X Metastable precipitate phase boundaries are difficult to ascertain experimentally and yet are important for controlling the microstructure of precipitation-hardenable alloys. We demonstrate how first-principles calculations of configurational and vibrational free energies can be used to predict precipitate phase boundaries of stable and metastable phases in Al–Cu alloys. Surprisingly, the formation entropy of a Cu impurity is found to be hugely positive(+2.7 k B /atom), leading to a dramatic enhancement in the solubility. The large entropy is dominated by the very low-frequency vibration of the small impurity atom (Cu) inside the large cage of the host (Al). The agreement between the GGA and experimental data is within 100 K for all phases, showing that accurate first-principles determination of metastable phase boundaries is now possible.

@article{0295-5075-73-5-719, abstract = {Metastable precipitate phase boundaries are difficult to ascertain experimentally and yet are important for controlling the microstructure of precipitation-hardenable alloys. We demonstrate how first-principles calculations of configurational and vibrational free energies can be used to predict precipitate phase boundaries of stable and metastable phases in Al–Cu alloys. Surprisingly, the formation entropy of a Cu impurity is found to be hugely positive(+2.7 k B /atom), leading to a dramatic enhancement in the solubility. The large entropy is dominated by the very low-frequency vibration of the small impurity atom (Cu) inside the large cage of the host (Al). The agreement between the GGA and experimental data is within 100 K for all phases, showing that accurate first-principles determination of metastable phase boundaries is now possible.}, added-at = {2010-11-03T17:57:04.000+0100}, author = {Ravi, C. and Wolverton, C. and Ozoliņš, V.}, biburl = {https://www.bibsonomy.org/bibtex/2e836185643475d5ec4a6c836f865697f/riche.ma}, description = {Predicting metastable phase boundaries in Al–Cu alloys from first-principles calculations of free energies: The role of atomic vibrations}, interhash = {5def21f9092cda8c7a8e66f11c37133a}, intrahash = {e836185643475d5ec4a6c836f865697f}, journal = {EPL (Europhysics Letters)}, keywords = {ab initio meta-stable phase thermodynamics}, number = 5, pages = 719, timestamp = {2010-11-03T17:57:04.000+0100}, title = {Predicting metastable phase boundaries in Al–Cu alloys from first-principles calculations of free energies: The role of atomic vibrations}, url = {http://stacks.iop.org/0295-5075/73/i=5/a=719}, volume = 73, year = 2006 }