Spinodal decomposition and the carbon solubility in BCC Fe-C

Abstract

Recent findings have indicated that (i) carbon solubility in ferrite is higher than predicted when in equilibrium with austenite, where a non-cubic structure of ferrite has been proposed, and (ii) local variations in carbon concentration consistently form within the matrix, thought to be the product of spinodal decomposition. These observations give rise to the scientific question of how carbon is distributed within ferrite, which remains under discussion in literature. The current study aims at establishing a thermodynamic explanation for the carbon solubility and partitioning within ferrite. Topics on carbon-competing processes such as spinodal decomposition in the Fe-C system and carbon segregation to defects are revisited.