We present a numerical study of the effect of a free-energy anisotropy of the solidsolid interphase boundaries on the formation of tilted lamellar microstructures during directional solidification of nonfaceted binary eutectic alloys. We used two different methods – phase-field (PF) and dynamic boundary-integral (BI) – to simulate the growth of periodic eutectic patterns in two dimensions. For ...

Laser surface melting has been applied to near eutectic NiO-YSZ sintered ceramics. The objective is to generate a functional gradient composite material with graded microstructure and composition. At low solidification rates the resultant material has a graded composition, with a severe NiO segregation towards the surface. A thick NiO layer whose thickness depends on the travelling speed is for...

In the past 50 years, there has been increasing interest-both theoretically and experimentally-in the problem of pattern formation of a moving boundary, such as a solidification front. One example of pattern formation is that of irregular eutectic solidification, in which the solid-liquid interface is non-isothermal and the interphase spacing varies in ways that are poorly understood. Here, we ...

The surface structure of the liquid phase of the Au72Ge28 eutectic alloy has been measured using resonant and nonresonant x-ray reflectivity and grazing incidence x-ray diffraction. In spite of the significant differences in the surface tension of liquid Ge and Au the Gibbs adsorption enhancement of Ge concentration at the surface is minimal. This is in striking contrast to all the other binary...

This article describes an innovative approach in which bimetallic alloy seeds of AuxAg1-x are used to enhance the growth kinetics of Ge nanowires, via a vapor-liquid-solid (VLS) growth technique. The decreased equilibrium concentration and increased supersaturation of Ge in the liquid alloy seeds, compared to pure Au seeds, results in favorable growth kinetics and the realization of high-aspect...

Neodymium aluminate coatings have been prepared in-situ by the laser zone melting (LZM) method, using a CO2 SLAB-type laser emitting at 10.6 µm. Polycrystalline Al2O3 commercial plates have been used as substrates, and coatings were prepared from the corresponding mixtures of powdered neodymium and aluminium oxides as starting materials. Microstructure, studied by SEM and phase composition, stu...

Al-5 wt pct Si master-alloys with controlled Sr and/or P addition/s were produced using super purity Al 99.99 wt pct and Si 99.999 wt pct materials in an arc melter. The master-alloy was melt-spun resulting in the production of thin ribbons. The Al matrix of the ribbons contained entrained Al-Si eutectic droplets that were subsequently investigated. Differential scanning calorimetry, thermodyna...

Di€erent doses of high-energy Si (0.2±4.5 MeV) were implanted in polycrystalline Au foils (35 lm thick) to form a low melting point Au±Si alloy which can be used for gold soldering. A Au±Si eutectic structure has been observed in the implanted Au foils after annealing at 400°C for 1 h. The Au±Si liquid phase was di€used in the polycrystalline Au foil along the grain boundaries which were ̄atten...

Metastable phase equilibria in the W-C system are presented in the vicinity of the metastable reactions involving W2C, WC1-x, and WC. Metastable phase boundaries were obtained by reproducing the stable boundaries using optimized Gibbs energy formulations and extrapolating them into regions of metastability. Four metastable reactions were obtained: a metastable congruent melting reaction of WC a...