Evolution of Non-metallic Inclusions in Solid Fe-Al-Ti-N Alloy During Heating

Control of non-metallic inclusions in terms of morphology, number density or composition is essential to produce steel products having the desired mechanical properties. Though many studies have been conducted to clarify various properties and evolution mechanisms of inclusions at steelmaking temperature, it has been reported that the states of inclusions in final products are significantly different from those in crude steels for some steel grades. The present study has focused on the evolution of oxide and nitride inclusions in solid Fe-Al-Ti-N alloys during heating to increase the understanding of inclusion evolution in a simplified metal system. Compositional and morphological change of initial inclusions, as well as precipitation and growth of new inclusions have been observed even when the alloy was in a solid state. This behavior has been observed due to the change of thermodynamic stability and solubility of existing phases in inclusions.