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Single crystal FeFP kinematics are widely used as the basis for many crystal plasticity models. Within this kinematic framework, geometrically necessary dislocations (GNDs) initially do not exist and then they evolve as needed in the material. A shortcoming of this kinematic model is that there is no rigorous way to define the initial and evolving GND state in the same manner. By augmenting the single crystal FeFP kinematics with a geometric argument, a consistent methodology for determining the initial and evolving GND state has been derived. The augmented kinematics describe GND related microstructural features in the undeformed material like low angle sub-grain boundaries and high angle grain boundaries. Therefore these kinematics are particularly applicable to polycrystalline materials.

This paper discusses in detail the development of a numerical model capable of simulating microstructural evolution and macroscopic deformation during sintering of complex powder compacts. The model based on the kinetic Monte Carlo (Potts) approach simulates grain growth, vacancy diffusion, and pore annihilation at grain boundaries, which is responsible for densification. Results of 2D simulations for perfect close-packed and random starting configurations are presented and discussed. The microstructural evolution is used to obtain the sintering stress––the macroscopic stress that is equivalent to the microstructural driving force for deformation.