Search arXiv⌕ Search

arXiv subjects

Koretaka Yuge

Publications and source records attributed to Koretaka Yuge.

56 records · Page 4Linked to original sources

Crystal lattice rules disordered states

Based on classical statistical thermodynamics, we develop a theoretical approach that provides new insight into how macroscopic and microscopic physical properties are bridged via crystal lattice for condensed mat- ters. We find that in order to determine macroscopic physical properties and their temperature dependence in equilibrium disordered state, information about a few specially selected microscopic states, established from geometrical characteristics of the crystal lattice, is sufficient. These special states are found to be independent of constitument elements as well as of temperature, which is in contrast to the standard conception in statistical thermodyanamics where a set of microscopic states mainly contributing to determining macroscopic physical properties depend on temperature and constituent elements. Validity and applicability of the theoretical ap- proach is confirmed through prediction of macroscopic physical properties in practical alloys, compared with prediction by full thermodynamic simulation. The present findings provide efficient and systematic prediction of macroscopic physical properties for equilibrium disordered states based on those for special microscopic states without any information of interactions for given system.

cond-mat.mtrl-sci↗

Phase-field study on the segregation mechanism of Cr to lamellar interface in C40-NbSi2/C11b-MoSi2 duplex silicide

Cr-segregation to a lamellar interface in NbSi2/MoSi2 duplex silicide has been examined by a newly developed phase-field model. The model can take into account the segregation energy evaluated by a first principles calculation to reflect the chemical interaction between solute atoms and the interface in addition to the elastic interaction. Cr segregation occurs at the interface in the case with segregation energy whereas no segregation occurs in the case with only elastic interaction. However, the segregation is much smaller than that observed in the experiment when the segregation energy was evaluated by the first principles calculation without lattice vibration (i.e. for 0 K). Another simulations with the segregation energy with lattice vibration results in segregation comparable to that in the experiment. Thus, it has been revealed that the solute-interface chemical interaction and its temperature dependence is responsible for the interfacial segregation of Cr.

cond-mat.mtrl-sci↗