A subnanoscale study of the nucleation, growth, and coarsening kinetics of Cu-rich precipitates in a multicomponent Fe-Cu based steel

The nucleation, growth, and coarsening kinetics of Cu-rich precipitates in a multicomponent Fe-Cu based steel, containing 1.17 at.% Cu, aged at 500 degrees C for up to 1024 h are investigated. The temporal evolution of the precipitate, heterophase interface, matrix compositions and precipitate morphology are presented. Coarsening temporal exponents are determined for mean radius, < R(t)>, number density, N(V)(t), and supersaturations, and are compared to the Lif-shitz -Slyzov-Wagner model for coarsening, modified for multicomponent alloys by Umantsev and Olson. The experimental results indicate that the alloy does not strictly follow Umantsev-Olson model behavior. Additionally, we compare the results to an investigation of a similar multicomponent steel containing 1.82 at.% Cu and to results in the literature. Furthermore, we present a Thermo-Calc determined phase diagram.