Mutliscale homogenization of elasticity and plasticity in hypereutectoid steels

Abstract

Hypereutectoid steels are of great use for the cable industry due to their good hardness and toughness due to their pearlitic microstructure, which is strongly influenced by the presence and characteristics of the proeutectoid grain boundary cementite phase. Pearlite may be lamellar or globular and grain boundary cementite may form a continuous or fragmented film. Understanding and forecasting the relation between the microstructure and the mechanical properties presents a major industrial relevance. For this purpose, we have recently realized the multiscale modeling of macroscopic elastic properties of polycrystalline hypereutectoid steel based on the elastic properties of the constituent phases ferrite and cementite through successive homogenization steps at successive scales using the Eshelby matrix-inclusion approach and the definition of volume elements following quantitative microstructural criteria due to the rule of separation of scales [1]. Various homogenization approaches are used at the different steps depending on the morphology of the microstructure, such as for example the classical or generalized self-consistent scheme for polycrystalline aggregates. When plasticity is involved, the self-consistent β-rule by Cailletaud and Pilvin [2] is used for scale transition, which obeys non-linear evolution with respect to plastic strain. The presented model can assist understanding of the effect of microstructural features such as the spheroidisation of grain boundary cementite on the ductility of hypereutectoid steel. [1] M. Vogric, E. Povoden-Karadeniz, Int. J. Mater. Res., Vol. 112, 5, 2021, 348-358 [2] P. Pilvin, G. Cailletaud, in Creep in Structures, Vol. 4, 1990, 171-178