Ferrite precipitation in quaternary Fe–C–X1–X2 systems using high-throughput approaches

This study investigates the effect of composition on ferrite growth kinetics in quaternary Fe–C–X1–X2 systems (X: Ni, Cr, Mo) using a high-throughput methodology. This study provides the largest dataset to date on ferrite growth kinetics in multi-component steels, offering novel insight into the behavior of these complex systems. To this end, high-energy X-ray diffraction is utilized to gather kinetic data in situ along composition gradients, leading to the measurement of phase transformation kinetics maps in compositional space. The obtained data is compared to predictions from various models describing ferrite growth kinetics in low-alloy steels. The modified "three-jump" solute drag model is shown to describe best the ferrite growth kinetics in these quaternary systems, without the need for additional calibration or fitting parameters. The success of this model is attributed to its consideration of individual solute interactions with the interface and inter-elemental interactions. The findings of this study provide valuable insight for robust modeling of phase transformations and microstructural evolution in multi-component steels, a critical tool in accelerating alloy optimization and in enhancing process control.