Study of the influence of alloying elements on Cu precipitation in steel by non-classical nucleation theory

The influence of Mn and Ni on Cu precipitation in body-centered cubic (bcc) Fe-Cu alloys was studied by means of Cahn-Hilliard non-classical nucleation theory and Langer-Schwartz simulation. The concentration profiles of Cu nuclei calculated in alloys of compositions near the ternary miscibility gap showed that Mn and Ni were enriched away from the center of a nucleus. Both elements decreased the work for the formation of a bcc Cu nucleus from that in a binary alloy of the same Cu content. Simulations of Cu precipitation during isothermal aging showed that the calculated reduction in the work of critical nucleus formation in the presence of alloying elements led to an increase in the number of Cu particles that are comparable with experimental observations. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.