Nikelin P-T diyagramının moleküler dinamik yöntemi ile hesaplanması

Metalik malzemelerin faz diyagramlarının belirlenmesi hem teknolojik hem de bilimsel açıdan önem taşır. Faz diyagramlarının teorik olarak belirlenmesinde büyük ölçüde Gibbs serbest enerjisinden yararlanılır. Moleküler dinamik benzetim yöntemlerinde serbest enerji doğrudan hesaplanabilen bir nicelik değildir. Bu nedenle çeşitli yaklaşımlar yapılır. Bu yaklaşımlar harmonik ve anharmonik olmak üzere iki grupta toplanabilir. Bu çalışmada, nikelin atomları arasındaki etkileşmeler Morse potansiyel enerji fonksiyonu kullanılarak modellenmiş ve sisteminin P-T faz diyagramı moleküler dinamik benzetim çalışmaları yardımıyla hesaplanmıştır. Ayrıca, sistem için hacim modülü ve termal genleşme katsayısı hesaplanmıştır. Elde edilen sonuçlar, Gömülmüş Atom Metodu sonuçları ve deneysel veriler ile karşılaştırılmıştır.

The calculation of P-T diagram for nickel using molecular dynamics method

Theoretical determination of phase diagrams of metallic substances is very important from both technological and scientific point of views. The Gibbs free energy is widely used in the calculation of the equilibrium phase diagrams. The free energy is not directly calculated in molecular dynamics simulation, but it is calculated by some approaches in two groups, harmonic and anharmonic. In this study, interatomic interactions in nickel are modelled by Morse potential energy function and P-T diagram of the system are calculated by means of molecular dynamics simulations. In addition, bulk modulus and thermal expansion coefficient of the system have been calculated. The results have been compared with the results of Embedded Atom Method and experimental data.

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