Development of phase diagram calculating codes based on bond order potentials

点击翻译按钮获取中文摘要

For the purpose of reliable calculations on free energies on elemental p-T diagram and binary phase diagram, we checked the effects of1. many body interactions of enthalpy changes, and2. anharmonic vibrational entropies.1. Many body interactionsThe enthalpy changes arised from the environment dependency of chemical bondings are predicted by bond order potentials based on Tight binding approximation. We developed parallel code and applied them to predict formation enthalpies of dilution limit alloys.2. Anharmonic vibrational entropiesThermal expansion and allotropic phase transitions are controlled by anharmonic effects of vibration entropies, which is reliably estimated by Frenkel method in Monte Cargo simulations. We developed also paralled code and applied it on bcc-hcp transition in Ti.Based on these simulations we also developed new method of reliable prediction on free energy changes of precipitate nucelations.We opened some of these developed codes in public, and the others are in progress.