Precipitation of TiS in Al–Ti Simultaneously Deoxidized Steel

Herein, the precipitation of TiS in an Al–Ti simultaneously deoxidized steel is observed, and the results confirm the precipitation of single TiS, two‐layered oxide (Al 2 O 3 or TiO x )–TiS composite, and three‐layered Al 2 O 3 –TiO x –TiS composite inclusions in the steel. Thermodynamic calculations reveal that TiS precipitated in the experimental steel during the solidification process when the solid fraction ( x s ) is 0.880. In addition, the precipitation of TiO x during solidification depends on the equilibrium partition of O. When the O content in steel is very low, TiS rather than TiO x is precipitated. In addition, the enrichment of O in the residual liquid steel results in the precipitation of TiO x during the solidification process. Oxide–TiS is formed by TiS precipitation on the surface of Al 2 O 3 and TiO x precipitation in the liquid steel or at the initial stage of solidification. However, Al 2 O 3 –TiS is formed only in preformed solid steel with low oxygen content. The lattice misfit results suggest that it is easier to match TiS to TiO and TiO 2 , while the misfit of TiS(001)/bcc Fe(100) is 6.06.