Phase field modelling of microstructural evolution during the quenching and partitioning treatment in low-alloy steels

作者：Mecozzi M G^*; Eiken J; Santofimia M J; Sietsma J

来源：Computational Materials Science, 2016, 112: 245-256.

DOI：10.1016/j.commatsci.2015.10.048

• Phase field model
• Carbon diffusion
• Austenite stability

A multiphase-field model (PFM) was applied to study the microstructure development during rapid cooling from the austenitising temperature to the quenching temperature and the carbon distribution between martensite (described as supersaturated ferrite) and austenite during holding at a selected "partitioning" temperature.
Although the modelling does not really simulate martensitic transformations, the morphology of acicular ferrite/austenite microstructure developed during cooling resembles the experimental martensite/residual austenite microstructure at the quenching temperature quite well. The carbon partitioning between the carbon supersaturated martensite and the austenite is simulated for different partitioning conditions. Applying a criterion to calculate the fraction of retained austenite at room temperature from the local austenite carbon content before the final quenching, the phase field model predicts the fraction and distribution of the retained austenite in the final steel microstructure for varying processing conditions in the quenching and partitioning process.
The comparison between 2D and 3D simulations shows that 2D simulations predict a higher retained austenite fraction than the 3D ones. Despite the different carbon diffusion behaviour in 2D and 3D space, which mainly affects the retained austenite fraction, the morphology and distribution of the retained austenite in both 2D and 3D simulations are in good agreement with the experimental observations.

• 出版日期2016-2