Induced side-branching in smooth and faceted dendrites: theory and phase-field simulations.

The present work is devoted to the phenomenon of induced side branching stemming from the disruption of free dendrite growth. We postulate that the secondary branching instability can be triggered by the departure of the morphology of the dendrite from its steady state shape. Thence, the instability results from the thermodynamic trade-off between non monotonic variations of interface temperature, surface energy, kinetic anisotropy and interface velocity within the Gibbs-Thomson equation.

Size-Dependent Solute Segregation at Symmetric Tilt Grain Boundaries in -Fe: A Quasiparticle Approach Study.

In the present work, atomistic modeling based on the quasiparticle approach (QA) was performed to establish general trends in the segregation of solutes with different atomic size at symmetric ⟨100⟩ tilt grain boundaries (GBs) in -Fe. Three types of solute atoms X, X and X were considered, with atomic radii smaller (X), similar (X) and larger (X) than iron atoms, respectively, corresponding to phosphorus (P), antimony (Sb) and tin (Sn). With this, we were able to evidence that segregation is dominated by atomic size and local hydrostatic stress.

Growth kinetics and morphology of snowflakes in supersaturated atmosphere using a three-dimensional phase-field model.

Simulating ice crystal growth is a major issue for meteorology and aircraft safety. Yet, very few models currently succeed in reproducing correctly the diversity of snow crystal forms, and link the model parameters to thermodynamic quantities. Here, we demonstrate that the new three-dimensional phase-field model developed in Demange et al.

Instrumentation for ice crystal characterization in laboratory using interferometric out-of-focus imaging.

Airborne characterization of ice crystals has important applications. The extreme difficulty of realizing in situ tests requires the development of a complete instrumentation in the laboratory. Such an installation should enable design, development, test, and calibration of instruments in conditions as close as possible to real ones.

Dynamical susceptibility of weakly interacting ferromagnetic nanoclusters.

The ac-susceptibility of weakly interacting ferromagnetic nanoclusters located at the vertices of a periodic lattice in a static applied field is calculated using a perturbation theory. The samples are nonspherical which gives rise to predominant shape effects due to dipolar interactions. The effects observed on the maximum of the two components of the dynamical susceptibility when increasing the strength of the dipolar interactions are opposite for prolate and oblate samples.