Development of Data-Driven Interatomic Potential for Plasticity Analysis of Zinc Oxide Ceramics

The dislocation toughening of ceramics has attracted considerable attention in recent years [1-3] since ceramics are inherently brittle and, thus, do not have a wide range of structural applications. However, understanding at the atomic scale is still lacking. We studied the dislocation-dominated deformation of wurtzite-type zinc oxide (ZnO) ceramic by nanoindentation simulation. ZnO ceramics has recently emerged as a leading semiconducting metal oxide ceramic. We developed data-driven interatomic potentials based on density functional theory (DFT) energy and force databases, yielding DFT accuracy and large-scale atomic simulation (millions of atoms). Large-scale indentation simulations were performed using the developed interatomic potentials to study indentation-induced dislocation nucleation and propagation in ZnO ceramics. An unprecedented phenomenon occurred in which identical rectangular dislocation loops were continuously nucleated from a single dislocation source under the indenter, induced by basal-to-prism dislocation cross-slip. The resulting dislocation loops pile-up, in good agreement with experiments. This study not only demonstrates the effectiveness of data-driven interatomic potentials in the analysis of plastic deformation of ceramic materials, but also provides new insights into the dislocation-dominated deformation behavior of ceramics. Authors acknowledge the JSPS Postdoctoral Fellowships for Research in Japan (Standard) and the Grant-in-Aid for JSPS Research Fellow Grant No. 22F22056.<br/><br/><b>References</b><br/>[1] Cho, J. et al. High temperature deformability of ductile flash-sintered ceramics via in-situ compression. Nature communications 9, 1-9 (2018).<br/>[2] Porz, L. et al. Dislocation-toughened ceramics. Materials Horizons 8, 1528-1537 (2021).<br/>[3] Reddy, K. M. et al. Dislocation-mediated shear amorphization in boron carbide. Science advances 7, eabc6714 (2021).