pycalphad 0.4.1

pycalphad is a free and open-source Python library for designing thermodynamic models, calculating phase diagrams and investigating phase equilibria using the CALPHAD method. It provides routines for reading thermodynamic database (TDB files) and solving the multi-component, multi-phase Gibbs energy minimization problem. The purpose of this project is to provide any interested people the ability to tinker with and improve the nuts and bolts of CALPHAD modeling without having to be a computer scientist or expert programmer

Origin of Outstanding Phase and Moisture Stability in a Na₃P_1–<i>x</i>As_<i>x</i>S₄ Superionic Conductor

Sodium ion (Na) solid-state electrolytes (SSEs) are critical to address notorious safety issues associated with liquid electrolytes used in the current Na ion batteries. Fulfilling multiple innovations is a grand challenge but is imperative for advanced Na ion SSEs, such as a combination of high ionic conductivity and excellent chemical stability. Here, our first-principles and phonon calculations reveal that Na₃P_1–<i>x</i>­As_<i>x</i>S₄ (0 ≤ <i>x</i> ≤ 1) is a solid-state superionic conductor stabilized at 0 K by zero-point vibrational energy and at finite temperatures by vibrational and configurational entropies. Especially, our integrated first-principles and experimental approach indicates that Na₃P_1–<i>x</i>­As_<i>x</i>S₄ is dry-air stable. Additionally, the alloying element arsenic greatly enhances the moisture (i.e., H₂O) stability of Na₃P_1–<i>x</i>­As_<i>x</i>S₄ by shifting the reaction products from the easy-forming oxysulfides (such as Na₃POS₃ and Na₃PO₂S₂ with H₂S release) to the difficult-forming hydrates (such as Na₃P_1–<i>x</i>­As_<i>x</i>S₄·<i>n</i>H₂O with <i>n</i> = 8 and/or 9) due mainly to a weaker As–O affinity compared to that of P–O. The present work demonstrates that alloying is able to achieve multiple innovations for solid-state electrolytes, such as a desirable superionic conductor with not only a high ionic conductivity (for example, 1.46 mS/cm at room temperature achieved in Na₃P_0.62­As_0.38S₄) but also an excellent chemical stability with respect to temperature, composition, and moisture

Zinc-induced embrittlement in nickel-base superalloys by simulation and experiment

<p>The high cost of Re has driven interest in processes for recovering Re from scrap superalloy parts. In this work thermodynamic modelling is used to study Zn-induced embrittlement of a superalloy and to direct experiments. Treating superalloy powder with Zn vapour reduces the average particle size after milling from approximately m to 0.5–10 m, vs. m for untreated powder. Simulations predict the required treatment time to increase with temperature. Agreement between predictions and experiments suggests that an embrittling liquid forms in less than an hour of Zn vapour treatment between 950–1000 C and partial pressures of Zn between 14–34 kPa (2–5 psi).</p

Platelet Count and Platelet Indices at Various Stages of Normal Pregnancy in Smoking and Non-Smoking Women

Peer Reviewe

Microstructure of alloys (a,c) A6 and (b,d) A7 equilibrated at (a,b) 1273 K and (c,d) 1373 K.

<p>The bright precipitates are Y-containing intermetallics (noted MY).</p

Al-Co-Cr Isothermal section at 1273 K.

<p>Shown with phase equilibria data from Ishikawa et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121386#pone.0121386.ref013" target="_blank">13</a>]: 2-phase (엯), and 3-phase (▿). Experimental phase equilibria data from the present work: 2-phase (●), 3-phase (▲).</p

Calculated enthalpies of mixing for solution A2 and B2.

<p>These calculations are based on binary and ternary SQS calculations at 0 K with references taken as bcc-A2 for Al, Co, and Cr.</p><p>Calculated enthalpies of mixing for solution A2 and B2.</p

Model parameters and functions for the ternary Al-Co-Cr system.

<p>Only A2, B2, and σ binary parameters are listed in full for their importance, all other binary parameters can be found in the respective binary Al-Co[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121386#pone.0121386.ref016" target="_blank">16</a>], Co-Cr[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121386#pone.0121386.ref017" target="_blank">17</a>], and Al-Cr[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121386#pone.0121386.ref020" target="_blank">20</a>] references as well as the attached database file. Parameters are in units of J/mol-formula.</p><p>Model parameters and functions for the ternary Al-Co-Cr system.</p

XRD analysis of selected alloy phase constitutions at 1273 K and 1373 K.

<p>Note that preferential orientations inherent to cast microstructures were still present after annealing. Specimens were rotated in-plane to ensure that all phases were detected.</p

Various properties of the Al, Co, Cr, and the end-members of B2 and σ.

<p>These properties are derived from the energy vs. volume curves using the 4-parameter Birch-Murnaghan EOS. <i>B</i>_<i>0</i> denotes the bulk modulus. The bulk modulus at room temperature of Al, Co, and Cr are also presented, as reported by Kittel [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121386#pone.0121386.ref056" target="_blank">56</a>]. Other experimental temperatures are shown if known; reported 0 K values are extrapolated from low temperature data.</p><p>Various properties of the Al, Co, Cr, and the end-members of B2 and σ.</p