Modeling and characterization of grain structures and defects in solidification

•Short review of solidification modeling at the mesoscopic scale.•Emphasis on approaches combining simulations and experiments.•Analytical and stochastic grain structure models are considered.•Modeling of defect formation, microporosity and hot tearing, is included.

The paper by Karma and Tourret (this volume) in this special issue focuses on multiscale modeling approaches ranging from atoms to microstructure. In the present one, the most recent and significant modeling contributions dealing with the scale of solidification from microstructure to grain structure are briefly reviewed. The paper also covers modeling of defect formation during the last stage of solidification, namely porosity and hot tearing. As will be shown, the field of solidification has taken advantage of several simulation and experimental tools which have become increasingly powerful and accessible over the past decade. The emphasis will be put on complex 2D and 3D models for which correlations with in situ observations using synchrotron radiation and/or combined orientation and metallography imaging have been made.