Dendrite growth behavior in directionally solidified Fe–C–Mn–Al alloys

Abstract

In this study, a series of directional solidification experiments were conducted to investigate the dendritic growth behavior in Fe–C–Mn–Al alloys with varying C contents (0.06, 0.24 and 0.68 wt%). Because of the large compositional undercooling at the front of the solid–liquid interface, dendrites developed at various growth velocities. Under the experimental conditions in the present study, the relationships between the primary dendrite arm spacing (PDAS) and growth velocity for the 0.06C, 0.24C and 0.68C alloys were λ0.06C = 11.75·V−0.30, λ0.24C = 10.38·V−0.32, and λ0.68C = 10.56·V−0.31 respectively. Comparison of the experimental data with prediction models confirmed that the PDAS of the Fe–0.68C–18.02Mn–1.35Al alloy can be predicted using the Kurz-Fisher model. The length of the mushy zone increased, and the high-temperature solidification mode changed with increasing C content, leading to complex changes in the PDAS. The results indicate that the solidification structure of Fe–C–Mn–Al alloys can be refined by increasing the growth velocity and that modifying the C content can be beneficial in avoiding the peritectic reaction.