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Computational study of the equilibrium concentrations of point defects in B2-RuAl

Sot R., Gokiel M., Garbacz H., Kurzydłowski K. J.

Inżynieria Materiałowa

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2007

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Vol. 28, nr 3-4

463-467

EN

First principles supercell approach was employed to calculate the formation enthalpies of isolated point defects in stoichiometric B2-RuAl. To predict the thermal defect concentrations at finite temperatures, we adopted the statistical-mechanical Wagner-Schottky model in combination with our first principles calculated point defect formation enthalpies. Al-antisite defect was found to be the major defect in Al-rich side in B2-RuAl single phase alloys.

PL

Na drodze obliczeń z pierwszych zasad w ramach przybliżenia superkomórki, obliczono entalpie formacji poszczególnych defektów punktowych w siechiometrycznym B2-RuAl. W celu określenia równowagowej koncentracji defektów punktowych w skończonych temperaturach, użyto modelu Wagnera-Schottky'ego z zaimplementowanymi entalpiami formacji obliczonymi z pierwszych zasad. W zakresie stężeń bogatszym w udział, atomów Al w fazie B2-RuAI, głównymi defektami odpowiedzialnymi za odchylenie od lu stechiometrycznego są atomy Al w pozycjach rukturalnych.

2

Atomic modelling of point defects in B2-RuAl

Sot R., Kurzydlowski K. J.

Materials Science Poland

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2005

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Vol. 23, No. 2

407--411

EN

Ab initio calculations based on density functional theory (DFT) and the pseudopotential method have been used to study B2-structured RuAl. The structural parameters, volume changes of single defects and pressure caused by the presence of point defects in B2-RuAl intermetallic compound were computed by the ab initio pseudopotential method with the plane-wave basis set and a generalized gradient approximation (GGA). The calculated structural parameters are in good agreement with available experimental data.

3

Ab initio calculations of elastic properties of Ni3Al and TiAl under pressure

Sot R., Kurzydłowski K. J.

Materials Science Poland

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2005

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Vol. 23, No. 3

587--590

EN

The structural parameters and the elastic stiffness coeffcients of Ni3Al and TiAl under a pressure P were computed by the ab initio pseudopotential method with the plane-wave basis set and the generalized gradient approximtion (GGA). The pressure dependence of the elastic constants is an important characteristics for both Ni3Al and TiAl as these materials are frequently subject to varying pressures during processing. The bulk modulus was also calculated. Stress-strain relationships were used to obtain the elastic constants. The results are in good agreement with the available experimental data.