First-principles study for quasi-static growth model in FeAl intermetallic based on Wulff cluster model.

In order to investigate the structure of FeAl mesoscopic crystals segregating in liquid state alloys, we have determined their equilibrium structures (Wulff shape) based on the Wulff cluster model. For non-stoichiometric surface terminations, the chemical environment is taken into account through the chemical potential of the constituents. In this case, different cluster shapes change as a function of the chemical environment.

A New Theoretical Method for Studying Effects of Microstructure on Effective Thermal Conductivity of Vermicular Graphite Cast Iron.

To provide the basis for thermal conductivity regulation of vermicular graphite cast iron (VGI), a new theoretical method consisting of shape interpolation, unit cell model and numerical calculation was proposed. Considering the influence of the graphite anisotropy and interfacial contact thermal conductivity (ICTC), the effective thermal conductivity of a series of unit cell models was calculated by numerical calculation based on finite difference. The effects of microstructure on effective thermal conductivity of VGI were studied by shape interpolation.

Theoretical design of platinum-sliver single atom alloy catalysts with CO adsorbate-induced surface structures.

In this work, by combining density functional theory calculations and Monte Carlo simulations with cluster expansion Hamiltonian methods, we investigate the surface aggregation of Pt atoms on the Pt/Ag(111) surface under vacuum conditions and in the presence of CO. The results show the decisive influence of CO-CO interactions and reveal the competition between CO-metal interactions and CO-CO repulsion. Thus, in addition to evidence of reverse Pt segregation caused by CO adsorption, two methods for tuning the surface Pt atomic system synthesis are found, where the surface can be adjusted by tuning the CO coverage to obtain a larger number of monomers (0.

Theoretical and experimental study of the microstructure of a metallic melt in an InBi alloy based on the Wulff cluster model.

In this paper, the Wulff cluster model which has been proved to successfully describe the melt structure of pure metals, homogenous alloys and eutectic alloys has been extended to an alloy with intermetallic compounds (InBi). According to the cohesive energy and the solid-state XRD patterns, the most possible types of clusters in the melt are Bi and InBi. At relatively high temperatures, the superimposed XRD (simulated) patterns of Bi and InBi clusters are in good agreement with the experimental HTXRD patterns in terms of the position and intensity of the peaks.

A first-principles study of water adsorbed on flat and stepped silver surfaces.

The structural, electronic and vibrational properties of a water layer on Ag(100) and Ag(511) have been studied by first-principles calculations and molecular dynamics simulations. The most stable water structure on the Ag(100) and Ag(511) surfaces have been obtained. The AIMD results showed rather high stability of the water layer on the stepped surface at 140 K, indicating a crystal-like structure with long-range ordering.

A casting combined quenching strategy to prepare PdAg single atom alloys designed using the cluster expansion combined Monte Carlo method.

In this work, the surface structure of a PdAg alloy is investigated by cluster expansion (CE) combined Monte Carlo (MC) simulations. All systems with different component proportions show an obvious component segregation corresponding to the depth from the surface. A significant amount of Ag is observed on the first layer, and Pd is concentrated significantly on the second layer.

Gold Carbide: A Predicted Nanotube Candidate from First Principle.

In the present work, density functional theory (DFT) calculations were applied to confirm that the gold carbide previously experimentally synthesized was AuC film. A crucial finding is that these kinds of AuC films are self-folded on the graphite substrate, leading to the formation of a semi-nanotube structure, which significantly diminishes the error between the experimental and simulated lattice constant. The unique characteristic, the spontaneous archlike reconstruction, makes AuC a possible candidate for self-assembled nanotubes.

The structure of metallic melts in eutectic alloys based on the Wulff cluster model: theory meets experiment.

In the present work, the Wulff cluster model, which has been proved to be successful for pure metals and homogeneous alloys, has been extended to eutectic alloys (Ag-Cu and Al-Si). In our model, the shapes of the clusters in melts were determined by the interfacial energy calculated by density functional theory (DFT) of different facet families based on Wulff theory. The cluster size was given by the pair distribution function (PDF) g(r), which was converted from experimental high-temperature X-ray diffraction (HTXRD).

The structure of metallic melts in binary homogenous alloys: a thermodynamical understanding from the Wulff cluster model.

In the present work, a new liquid metal model (Wulff cluster model) which has been proved to describe the structures of pure metal melts has been extended to binary homogeneous alloy melts (Cu-Ni and Ag-Au). The shapes of the nano-particles are determined by surface energies of different families of crystal planes, calculated by density functional theory (DFT), whereas the size was given by the pair distribution function (PDF) g(r) which was converted from experimental high-temperature X-ray diffraction (HTXRD). We demonstrated that the simulated X-ray diffraction (XRD) curves from present models match the experimental results quite well at high temperatures above the liquid-solid two-phase region, including not only the position and width of the peaks but also the relative intensity of the first and second peaks.