PFHub: The Phase-Field Community Hub.

Scientific communities struggle with the challenge of effectively and efficiently sharing content and data. An online portal provides a valuable space for scientific communities to discuss challenges and collate scientific results. Examples of such portals include the Micromagnetic Modeling Group (μMAG [1]), the Interatomic Potentials Repository (IPR [2, 3]) and on a larger scale the NIH Genetic Sequence Database (GenBank [4]).

Simulation and analysis of -Ni cellular growth during laser powder deposition of Ni-based superalloys.

Cellular or dendritic microstructures that result as a function of additive manufacturing solidification conditions in a Ni-based melt pool are simulated in the present work using three-dimensional phase-field simulations. A macroscopic thermal model is used to obtain the temperature gradient and the solidification velocity which are provided as inputs to the phase-field model. We extract the cell spacings, cell core compositions, and cell tip as well as mushy zone temperatures from the simulated microstructures as a function of .

Simulation of temperature, stress and microstructure fields during laser deposition of Ti-6Al-4V.

We study the evolution of prior columnar phase, interface phase, and phase during directional solidification of a Ti-6Al-4V melt pool. Finite element simulations estimate the solidification temperature and velocity fields in the melt pool and analyze the stress field and thermal distortions in the solidified part during the laser powder bed fusion process. A phase-field model uses the temperature and velocity fields to predict the formation of columnar prior-(Ti) phase.

On the primary spacing and microsegregation of cellular dendrites in laser deposited Ni-Nb alloys.

In this study, an alloy phase-field model is used to simulate solidification microstructures at different locations within a solidified molten pool. The temperature gradient and the solidification velocity are obtained from a macroscopic heat transfer finite element simulation and provided as input to the phase-field model. The effects of laser beam speed and the location within the melt pool on the primary arm spacing and on the extent of Nb partitioning at the cell tips are investigated.

Windowless CdSe/CdTe solar cells with differentiated back contacts: J-V, EQE, and photocurrent mapping.

This study presents windowless CdSe/CdTe thin film photovoltaic devices with in-plane patterning at a submicrometer length scale. The photovoltaic cells are fabricated upon two interdigitated comb electrodes prepatterned at micrometer length scale on an insulating substrate. CdSe is electrodeposited on one electrode, and CdTe is deposited by pulsed laser deposition over the entire surface of the resulting structure.

Multicomponent phase-field model for extremely large partition coefficients.

We develop a multicomponent phase-field model specially formulated to robustly simulate concentration variations from molar to atomic magnitudes across an interface, i.e., partition coefficients in excess of 10±23 such as may be the case with species which are predominant in one phase and insoluble in the other.

The effect of substrate material on silver nanoparticle antimicrobial efficacy.

With the advent of nanotechnology, silver nanoparticles increasingly are being used in coatings, especially in medical device applications, to capitalize on their antimicrobial properties. The attractiveness of nanoparticulate silver systems is the expected increased antimicrobial efficacy relative to their bulk counterparts, which may be attributed to an increased silver ion (Ag+) solubility, and hence availability, that arises from capillarity effects in small, nanometer-sized particles. However, a change of the material upon which the antimicrobial nanoparticulate silver is deposited (herein called "substrate") may affect the availability of Ag+ ions and the intended efficacy of the device.

Predicting microstructure development during casting of drug-eluting coatings.

We have devised a novel diffuse interface formulation to model the development of chemical and physical inhomogeneities, i.e. microstructure, during the process of casting drug-eluting coatings.