Modelling of Micro-Plasticity Evolution in Crystalline Materials

In this work, a micromechanical finite element model is presented to investigate micro-plasticity evolution in crystalline materials, with a comprehensive consideration of microstructural interactions, including morphology-based intragranular stress-strain response and the strain gradient induced scale effect. A dislocation-mechanics based crystal plasticity formulation has been employed to account for slip based inelastic deformation. A polycrystalline model has been constructed using the Voronoi tessellation technique to represent the microstructure of a martensitic power plant steel, P91. The model has been validated through a uniaxial tensile test. The effects of strain gradient have been examined at both macroscopic and microscopic levels and the importance of accounting for strain gradient effects in the prediction of local deformation states is discussed for P91.