Geometric and Constitutive Modeling of MgO–C Refractories Based on Recyclates for Thermomechanical Simulations

ABSTRACT Refractories are polycrystalline, porous, heterogeneous, and nonmetallic materials utilized as protective liners in high‐temperature manufacturing processes. Microscopic and mechanical characterization studies of MgO–C refractories in the literature show a strong correlation between the underlying microstructure and the thermomechanical response of these materials. The present study focuses on developing a simulation tool that evaluates the thermomechanical behavior of recycled refractories, specifically the influence of microstructural features on their thermal shock resistance. In contrast to prior methodologies, the intricate and heterogeneous microstructure of MgO–C is conceptualized as a three‐phase composite comprising coarse magnesia aggregates, graphite flakes, and an effective matrix. The homogenized matrix material is presumed to consist of fine magnesia, carbonaceous binders, additives, and pores, which are not spatially resolved in the current approach. Using open‐access Python packages, a preprocessing tool with a graphical user interface (GUI) is developed to synthetically generate an idealized 2D microstructure representation from statistical data, such as particle size distributions and phase volume fractions. According to the current hypothesis and experimental findings, the principal mechanism of damage in these materials involves the debonding of phase interfaces due to thermally induced stresses. This interface damage is modeled using the cohesive zone approach. Basic hot thermal shock simulations are performed employing the synthetically generated microstructure to investigate the influences of thermal expansion coefficient mismatches and thermal gradients on the local interface damage.