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Solidification modes during additive manufacturing of steel revealed by high-speed X-ray diffraction



Hans-Henrik König, Niklas Holländer Pettersson, A Durga, Steven Van Petegem, Daniel Grolimund, Qilin Guo, Chihpin Chuang, lianyi Chen, Christos Oikonomou, Fan Zhang, Greta Lindwall


Solidification during fusion-based additive manufacturing (AM) is characterized by high solidification velocities and high thermal gradients, two factors that control the solidification mode of AM metals and alloys. Using two synchrotron-based, in situ setups, we perform high-speed X-ray diffraction measurements to investigate the impact of the solidification velocities and thermal gradients on the solidification mode of a hot-work tool steel over a wide range of thermal conditions of relevance to AM of metals. The solidification mode of primary δ-ferrite is observed at a cooling rate of 2.12 × 104 K/s, and at a higher cooling rate of 1.5 × 106 K/s, δ-ferrite is suppressed, and primary austenite is observed. The experimental thermal conditions are evaluated and linked to a Kurz-Giovanola-Trivedi (KGT) based solidification model. The modeling results show that the predictions from the multicomponent KGT model agree with the experimental observations. This work highlights the role of in situ XRD measurements for a fundamental understanding of the microstructure evolution during AM and for validation of computational thermodynamics and kinetics models, facilitating parameter and alloy development for AM processes.
Acta Materialia


additive manufacturing, metals, solidification, phase transition, high-speed X-ray diffraction


König, H. , Pettersson, N. , Durga, A. , Van Petegem, S. , Grolimund, D. , Guo, Q. , Chuang, C. , Chen, L. , Oikonomou, C. , Zhang, F. and Lindwall, G. (2023), Solidification modes during additive manufacturing of steel revealed by high-speed X-ray diffraction, Acta Materialia, [online],, (Accessed April 20, 2024)
Created March 1, 2023, Updated February 2, 2023