Modeling of chromium precipitation in Fe-Cr alloys
2004 (English)In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 69, 094103- p.Article in journal (Refereed) Published
We have implemented a set of Embedded Atom Method (EAM) potentials for simulation of Fe-Cr alloys. The functions for the pure elements were fitted to the respective elastic constants, vacancy formation energy, and thermal expansion coefficients. For Cr, properties of the paramagnetic state were applied, providing a positive Cauchy pressure and hence applicability of the EAM. By relaxing the requirement of reproducing the pressure-volume relation at short interaction distances, stability of the <110> self-interstitial could be obtained. Our Fe-potential gives E-<110>(f)-E-<111>(f)=-0.23 eV. Mixed Fe-Cr pair potentials were fitted to the calculated mixing enthalpy of ferromagnetic Fe-Cr, which is negative for Cr concentrations below 6%. Simulation of thermal aging in Fe-Cr alloys using a potential fitted to the mixing enthalpy of Fe-20Cr exhibited pronounced Cr-precipitation for temperatures below 900 K, in agreement with the phase diagram. No such ordering was observed at any temperature using a potential fitted to the mixing enthalpy of Fe-5Cr. Applied to recoil cascade simulations the new potentials predict a smaller number of surviving defects than potentials found in the literature. We obtain a cascade efficiency of 0.135 NRT for damage energies inbetween 10 and 20 keV. An enhanced probability for Cr atoms to end up in defect structures is observed.
Place, publisher, year, edition, pages
2004. Vol. 69, 094103- p.
computer-simulation, alpha-iron, elastic-constants, transition-metals, bcc iron, defect, irradiation, steels, decomposition, temperature
IdentifiersURN: urn:nbn:se:kth:diva-8805DOI: 10.1103/PhysRevB.69.094103ISI: 000220812800036ScopusID: 2-s2.0-2142771770OAI: oai:DiVA.org:kth-8805DiVA: diva2:14242
QC 201012082005-11-232005-11-232016-04-19Bibliographically approved