Hamza Yaşar OCAK, Ali ÇETİN, Gencer SARIOĞLU

Fe ve Fe - %25 Al için maksimum streslerin (hkl) düzlemlerinde teorik olarak hesaplanması

Oda sıcaklığında Fe ve Fe-% 25 Al (Fe3Al) kristalleri bcc yapıda olup, deneysel örgü parametreleri (a0) 2.87 Å ve 2,8964 Å dur. İç etkileşme enerjileri birbirlerine çok yakın olan Fe ve Fe3Al kristallerinin, fiziksel özellikleri birçok yönden incelenmektedir. Temel fiziksel parametreler (hkl) kristal düzlemlerinde, farklı büyüklüklere sahiptir. Bu çalışmada, elastik parametrelerden, maksimum stressler (Thkl), hem Fe hem de Fe3Al kristalleri için (hkl) düzlemlerinde incelendi. Bunun için, öncelikle Wien2k yöntemi kullanılarak ikinci derece elastik sabitler (C11, C12 ve C44) kübik simetri için hesaplandı. Kristallerin örgü parametreleri ve saçılma açıları (2θ) pik genişliklerini (βhkl) bulmak için kullanıldı. Düzlemlere göre hesaplanan bazı elastik parametreler, farklı denklemlerden hesaplanan sonuçlarla karşılaştırıldı. Kristal boyutlarına (Dhkl) bağlı olan dislokasyon yoğunluğunlukları (δhkl) da (hkl) düzlemlerinde incelendi. Elde edilen tüm sonuçlar, (hkl) düzlemleri ve bazı [hkl] doğrultularına göre yorumlanarak, yakın çalışma sonuçları ile karşılaştırıldı. Bu tarz analitik incelemelerin (222) düzlemine kadar genişletilmesinin yeterli olabileceği sonucuna ulaşıldı.

Theoretical calculation of maximum stresses (hkl) planes for Fe and Fe - 25% Al

At room temperature, Fe and Fe-25% Al (Fe3Al) crystals are in bcc structure and the experimental lattice parameters (a0) are 2.87 Å and 2.8964 Å. The physical properties of Fe and Fe3Al crystals, whose internal interaction energies are very close to each other, are investigated from many perspectives. The basic physical parameters have different sizes in the (hkl) crystal planes. In this study, the maximum stresses (Thkl) were investigated from the elastic parameters in the (hkl) planes for both Fe and Fe3Al crystals. For this, second order elastic constants (C11, C12 and C44) were calculated first for cubic symmetry by using the Wien2k method. The lattice parameters of the crystals and scattering angles (2θ) were used to find the peak widths (βhkl). Some elastic parameters calculated with respect to the planes were compared with the results calculated from different equations. The dislocation densities (δhkl) related to crystal dimensions (Dhkl) were also studied in planes (hkl). All the obtained results were interpreted according to (hkl) planes and some [hkl] directions and compared with the results of other close studies. It has been reached that such analytical investigations could be extended to the (222) plane.

Keywords:

Fe and Fe3Al, maximum stress, young stability peak width, crystal dimension, dislocation intensity,

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