Interfacial debonding in compacted graphite iron: effect of thermal loading

In this work, graphite debonding under thermal loading in compacted graphite iron (CGI) is investigated, employing a microstructure-based modelling approach. CGI has a complex microstructure, comprising graphite particles of different shapes, sizes and orientations embedded in an iron matrix. As a result of mismatch in coefficients of thermal expansion of constituents, thermal load can result in damage due to interfacial debonding. To evaluate this phenomenon, representative volume elements of CGI microstructures are studied using finite-element simulations. Specific inputs in the model are provided through statistical analysis of SEM micrographs. Further, the influence of boundary conditions and incorporation of an interfacial layer is discussed. The obtained results demonstrate that the onset of matrix plasticisation and graphite decohesion are sensitive to the adopted modelling assumptions.