Thermodynamics of ordered and disordered phases in the binary Mo-Ru system
2007 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 75, no 18Article in journal (Refereed) Published
We have performed ab initio calculations of the mixing enthalpy for the Mo-Ru alloy system. Both completely random alloys on the fcc, bcc, and hcp lattices as well as ordered and partially ordered structures based on the hcp lattice and a sigma phase have been examined. Further, we have performed a ground-state search for the Ru-rich region using ab initio derived effective interactions, and find a series of structures below the tie line of the simple compounds. Using the structures from this ground-state search, we are able to make an estimation of the contribution to the total energy due to ordering effects in this system. We find unusually large deviations between calculated and experimental values of the mixing enthalpy for Ru-rich hcp alloys. Our calculations indicate, in agreement with experiment, that there are ordering trends in the system. However, even under assumption of maximal order theoretical results differ substantially from the experiment. Possible reasons for the disagreement are discussed.
Place, publisher, year, edition, pages
2007. Vol. 75, no 18
total-energy calculations, wave basis-set, ab-initio, alloys, metals, cr, approximation, molybdenum, transition, state
IdentifiersURN: urn:nbn:se:kth:diva-16668DOI: 10.1103/PhysRevB.75.184203ISI: 000246890600028ScopusID: 2-s2.0-34347348271OAI: oai:DiVA.org:kth-16668DiVA: diva2:334711
QC 201005252010-08-052010-08-05Bibliographically approved