Tensile and compressive mechanical properties of nanocrystalline calcite with grain size effect

Abstract

Abstract Calcite is one of the most main components of microbially induced calcium carbonate precipitation (MICP). With the in-depth research of MICP, the mechanical properties of nanocrystalline calcite attract much attention. In this paper, the deformation and failure behaviors of nanocrystalline calcite under a uniaxial tensile or compressive condition are studied by molecular dynamics simulation, and then the dominant deformation and failure mechanisms, as well as their grain size effect, are analyzed. The results show that the grain boundary densification dominates the elastic deformation, while the intragranular phase transition dominates the plastic deformation. Compared with single-crystal calcite, the elastic modulus of nanocrystalline calcite is significantly reduced and its ultimate strength is decreased by more than 50%. Nanocrystalline calcite has stronger plastic deformation ability in compression than in tension. Its tensile and compressive elastic moduli and peak stresses all increase with the average grain size. The effects of grain size on the limit stresses can be described by the inverse Hall–Petch equation. This study is helpful for tailoring the mechanical properties of MICP by the morphology of nanocrystalline calcite.