Alphonse Finel

Phase field methods and dislocations

Abstract We present a general formalism for incorporating dislocations in Phase Field methods (PFM) based on the elastic equivalence between a dislocation loop and a platelet inclusion of specific stress-free strain. Dislocations may be elastically and dynamically coupled to any other field such as a concentration field. Special attention is paid to the treatment of dislocation cores after the discretization of real and reciprocal space required by the computer implementation of any PFM. In particular, we propose a method based on two length scales to account for dislocation cores much smaller than the grid spacing. The method is illustrated through the simulation of the motion of a dislocation loop in a microstructure representative of a late-stage γ/γ′ microstructure.

Coupling phase field and viscoplasticity to study rafting in Ni-based superalloys

An elasto-viscoplastic model is developed to study the microstructural evolution during creep loading in a model AM1 superalloy. Elastic anisotropy and inhomogeneity, as well as the description of long-range order in the γ ′ phase, are included in the model. Plastic activity is introduced using a continuum crystal plasticity framework at the mesoscale. Special attention is paid to the corresponding parameter identification from experiments. Two-dimensional simulations of creep in the [100] direction are performed, and the results are compared to the predictions of an elastic phase field model, in order to characterize the influence of plastic activity on the microstructural evolution. In particular, our simulations show that plastic activity in the γ channels significantly increases the rafting kinetics and allows misalignments of rafts with respect to cubic directions. The simulation results are critically discussed and improvements to the model are proposed.

Kinetics of the coherent order-disorder transition in Al 3 Zr

Within a phase field approach which takes the strain-induced elasticity into account, the kinetics of the coherent order-disorder transition is investigated for the specific case of

Long-range order and short-range order in Pd3V: Breakdown of the mean-field theory.

{\mathrm{Al}}_{3}\mathrm{Zr}

A phase field model for dislocation climb

alloy. It is shown that a microstructure with cubic

Multiscale Theory of Dislocation Climb

{L1}_{2}

Density-based crystal plasticity: From the discrete to the continuum

precipitates appears as a transient state during the decomposition of a homogeneous disordered solid solution into a microstructure with tetragonal

Influence of atomic size mismatch on binary alloy phase diagrams

{\mathrm{DO}}_{23}

A Vacancy Model of Pore Annihilation During Hot Isostatic Pressing of Single Crystals of Nickel-Base Superalloys

precipitates embedded into a disordered matrix. At low enough temperature, favored by a weak internal stress, only

Concentration variation of the effective pair interactions measured on the Pt-V system. Evaluation of the gamma expansion method

{L1}_{2}