There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

We present a new algorithm to generate Special Quasirandom Structures (SQS), i.e., best periodic supercell approximations to the true disordered state for a given number of atoms per supercell. The method is based on a Monte Carlo simulated annealing loop with an objective function that seeks to perfectly match the maximum number of correlation functions (as opposed to merely minimizing the distance between the SQS correlation and the disordered state correlations for a pre-specified set of correlations). The proposed method optimizes the shape of the supercell jointly with the occupation of the atomic sites, thus ensuring that the configurational space searched is exhaustive and not biased by a pre-specified supercell shape. The method has been implemented in the “mcsqs” code of the Alloy Theoretic Automated Toolkit (ATAT) in the most general framework of multicomponent multisublattice systems and in a way that minimizes the amount of input information the user needs to specify and that allows for efficient parallelization.

/pdf/efficient-stochastic-generation-of-special-quasirandom-svnfe83eez.pdf

Efficient stochastic generation of special quasirandom structures

The relative effects of pressure, temperature and oxygen fugacity on the solubility of sulfide in mafic magmas

Solidification microstructures: recent developments, future directions

Sn-rich alloys in the Sn-Ag-Cu system are being studied for their potential as Pb-free solders. Thus, the location of the ternary eutectic involving L, (Sn), Ag3Sn and Cu6Sn5 phases is of critical interest. Phase diagram data in the Sn-rich corner of the Sn-Ag-Cu system are measured. The ternary eutectic is confirmed to be at a composition of 3.5 wt.% Ag, 0.9 wt.% Cu at a temperature of 217.2±0.2°C (2σ). A thermodynamic calculation of the Sn-rich part of the diagram from the three constituent binary systems and the available ternary data using the CALPHAD method is conducted. The best fit to the experimental data is 3.66 wt.% Ag and 0.91 wt.% Cu at a temperature of 216.3°C. Using the thermodynamic description to obtain the enthalpy- temperature relation, the DTA signal is simulated and used to explain the difficulty of liquidus measurements in these alloys.

/pdf/experimental-and-thermodynamic-assessment-of-sn-ag-cu-solder-ohlm6kfv79.pdf

Experimental and thermodynamic assessment of Sn-Ag-Cu solder alloys

Phase equilibria in the M-In-P (M = transition metal) ternary systems is determined through a combination of thermodynamic calculation and experimentation. Palladium is identified as a particularly attractive metal for contacts to InP. One useful feature of this system for contact design is the occurance of Pd χ InP ternary phases. Additionally, Pdln is found to be in equilibrium with InP and is identified as a promising contact material to InP because of its high melting point, low resistivity, and favorable properties for processing. Progress in the development of Pdln-based contacts to InP is briefly discussed.

Metallurgical Behavior of the Metal-IN-P Systems: Implications for the Design of Contacts to Inp

Solid State Phase Equilibria in the Ga-Co-As System at 600 °C/ Fest-Phasen-Gleichgewichte im System Ga-Co-As bei 600 °C

Diffusion couple experiments were carried out for Mo/γ-TiAl at 900, 1000 and 1100°C for periods of time ranging from 121 to 553 hrs. Using the Boltzmann-Matano analysis, the two diagonal interdiffusion coefficients for the two phases formed in these couples were obtained assuming the cross diagonal terms to be negligible. These two phases are δ-(Mo, Ti)3Al and β-(Mo,Al)Ti. The three intrinsic diffusion coefficients were also obtained using the Darken-type relationships between the interdiffusion and intrinsic diffusion coefficients. The calculated interdiffusion coefficients from the three intrinsic diffusion coefficients are in reasonable accord with those obtained directly from the Boltzmann-Matano analysis.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1946427400319601

Interdiffusion Between Mo and TiAl

The Activity Coefficient of Nonmetallic Elements in Binary Liquid Alloys from a Nonrandom Solvation Shell Model

The phase changes of NiMn films, produced by co-sputtering from elemental targets on glass slides, were investigated using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The as-deposited NiMn thin films were found to be amorphous or nanocrystalline with a high defect density. When subjected to thermal annealing, the films exhibit four exothermic reactions as measured by DSC. The second and the third peaks were attributed to the formation of the fcc (A1) phase and the face-centered tetragonal (L10) phase, respectively. The first peak around 160 8C and last one at 440 8C could be due to oxidation and coarsening, respectively. D 2004 Published by Elsevier B.V.

Y. Austin Chang

Papers

Metallurgical Behavior of the Metal-IN-P Systems: Implications for the Design of Contacts to Inp

Solid State Phase Equilibria in the Ga-Co-As System at 600 °C/ Fest-Phasen-Gleichgewichte im System Ga-Co-As bei 600 °C

Interdiffusion Between Mo and TiAl

The Activity Coefficient of Nonmetallic Elements in Binary Liquid Alloys from a Nonrandom Solvation Shell Model

Short Communication Phase transformations in sputter deposited NiMn thin films