Simulations of precipitation in ferritic steels

Abstract

A new technique based on Monte Carlo random sampling has been proposed to simulate the precipitation kinetics in alloys. The new approach employs time dependent nucleation and diffusion laws, considers both intergranular and intra-granular precipitation, and also combines precipitation kinetics with intergranular segregation. The simulation can be used not only to predict the average size of precipitate phase particles, but also to predict particle size distributions, volume fraction, and interparticle spacing. The new approach overcomes the shortcomings of earlier model calculations where only the average size of the precipitate phase is considered. In addition, the proposed simulation overcomes the difficulty of connecting Monte Carlo steps to real time using the Metropolis algorithm. The approach has been used to simulate M₂₃C₆ precipitation kinetics in a creep resistant steel, P92: the results are in good agreement with published experimental measurements, and the model is believed to be applicable to other types of precipitates in different alloys.