Modeling And Simulation Of Precipitation Behavior For Low Carbon Steels With Second Phase Particles Using Phase Field Method

High strength and toughness is mainstream direction of steel development. Toughening technology and theoretical study is crucial to production and application of steel. It is generally thought that grain refinement is the most effective way to improve strength and toughness of steel. In practice, introduction or precipitation of the second phase particles can prevent grain growth to refine the final grain structure. With the application of alloying technology and controlled rolling and controlled cooling technology, alloyed and microalloyed steels with the second phase particles grain refinement techniques are widely developed.Research on precipitation of second phase particles, especially the kinetics behavior of precipitate is valuable work. However, few people conduct a comprehensive experimental study so far. This is mainly because the experimental conditions are harsh, long cycle, and far from the level of quantitative research. With the development of computational materials science, especially material microstructure evolution simulation, it is possible that computer simulation technology is used to carry out virtual experimental study of precipitation process of the second phase particles. Simulation study of the second phase particles precipitation behavior can lay foundation to improve the organizational structure and performance of alloy steel with the effective control of the second phase particles size, shape and distribution state.In view of the several computer simulation methods, the phase field model has a more rigorous thermodynamic basis and is more appropriate for dynamic simulation of complex systems research, so the development of the phase field model about precipitation of second phase particles in the steel is necessary. It is also a necessary supplementary research to our group’s microstructure evolution of second phase particle material.In this paper, research object is low-carbon steel with niobium which is the most common industrial applications. According to theories of phase field and thermodynamics, metals physics, base on model assumptions, Phase field model simulating precipitation of second phase particles of steel was established. Combined with thermodynamic software and physical significance of the model parameters, more accurate parameter values rule was identified. In accordance with the numerical algorithm, simulation applications were developed. With the development of image processing technology, evolution of particle morphology was shown. Simulation study of Behavior and variation of second phase particles precipitation was represented and explained.The results indicate that particle morphology evolution during random precipitation, single particle precipitation, two particle precipitation, square particle precipitation process can be accurately simulated by the phase field model. Second phase particles precipitate rule is obtained by corresponding kinetic quantitative analysis. This study gives us a virtual experimental methods and simulation techniques to understand law and mechanism of second phase particles precipitation in micro-alloy steel.