Iron Interstitial Defects Stability: Under the Uniaxial Stress Effect

Stres alanlarındaki kusur kinetiğinin anlaşılması, nükleer maddelerin bozulmasının çok boyutlu modellenmesi için önemlidir. Moleküler dinamik (MD) simülasyonu ile, formasyon ve göç enerjisi enerjileri, alfa Fe'de kendiliğinden oluşan atom (SIA) ve SIA kümeleri (1 ~ 3 geçiş reklamları) için değerlendirilmiştir. % 0 ~ 3 tek eksenli sürdürülebilir [100] gerilme etkileri SIAs ve halter konfigürasyonları için test edilmiştir. Kararlılık ile ilgili olarak, halter konfigürasyonları daha büyük suşlarda ve daha büyük kümelerde daha kararlı hale gelir. Hareketlilik için, sürdürülebilir gerilmeler altında tek SIA kusurlarının difüzyonu izlenmiştir. Serbest gerilme koşullarında, SIA kümelerinin difüzivitesi, doymuş gerilmede üç boyutlu (3D) ile bir boyutlu (1D) aşamalı bir geçişe sahiptir. 3D geçiş küçük kümeler ve alt gerilmeler için iken ve büyük ölçüde SIA hizalama konfigürasyonu için sunulurken, 1D geçişi büyük kümeler ve büyük gerginlik için gözlenmiştir. Çekme gerilmesi altında ve küçük kümeler için, difüzyon artırımı daha yüksek bir sıcaklıkta daha büyüktür. Bununla birlikte, sıcaklık etkisi daha büyük kümeler için küçüktür. Gerinim alanlarının bu etkileri, kusurlar ve uygulanan stres alanları arasındaki elastik etkileşim ile açıklanabilir

Tek Eksenli Stres Etkisi Altında Demir Çatlak Kusurları Kararlılığı

Understanding of defect kinetics under stress fields is important for multiscale modeling of nuclear materials degradation. By means of molecular dynamics (MD) simulation, the formation and migration energies were evaluated for self-interstitial atom (SIA) and SIA clusters (1~3 interstitials) in alpha Fe. Effects of 0~3% uniaxial tensile [100] strains were tested for SIAs of and dumbbell configurations. Regarding the stability, the dumbbell configurations becomes more stabilized at larger strains and larger clusters. For the mobility, the diffusion of single SIA defects under tensile stresses were traced. Under the free-strain condition, the diffusivity of the SIA clusters has a gradual transition from three dimensional (3D) to one dimensional (1D) at saturated strain. The 1D transition was observed for large clusters and large strain while the 3D transition was for small clusters and lower strains and presented mainly for the SIA alignment configuration. Under the tensile stress and for small clusters, diffusivity enhancement is bigger at a higher temperature. However, the temperature effect was small for larger clusters. These effects of strain fields can be explained by elastic interaction between defects and applied stress fields

PDF

___

[1]. Wang D., Gao N., Setyawan W., Kurtz R.J., Wang Z.-G., Gao X., He W.-H., Pang L.-L. Effect of Strain Field on Threshold Displacement Energy of Tungsten Studied by Molecular Dynamics Simulation, Chinese Phys. Lett. 33 (2016) 96102.
[2]. Banisalman M.J., Park S., Oda T. Evaluation of the threshold displacement energy in tungsten by molecular dynamics calculations, J. Nucl. Mater. 495 (2017) 277–284.
[3]. Beeler B., Asta M., Hosemann P., Grønbechjensen N. Effects of applied strain on radiation damage generation in body- centered cubic iron, J. Nucl. Mater. 459 (2015) 159-165.
[4]. Lewis T.A., Gao F., Bacon D.J.. Flewitt P.E.J. The influence of strain on defect generation by displacement cascades in alpha-Fe, Nucl. Instruments Methods Phys. Res. Sect. B Beam Interact. with Mater. Atoms. 180 (2001) 187– 193
[5]. Miyashiro S., Fujita S., Okita T. MD simulations to evaluate the influence of applied normal stress or deformation on defect production rate and size distribution of clusters in cascade process for pure Cu, J. Nucl. Mater. 415 (2011) 1–4.
[6]. Fu C., Willaime F. Stability and Mobility of Mono- and Di-Interstitials in -Fe, (2004) 1–4.
[7]. Osetsky Y.N., Serra A., Singh B.N., Golubov S.I. Structure and properties of clusters of selfinterstitial atoms in fcc copper and bcc iron, 8610 (2017).
[8]. Osetsky Y.N. Atomistic study of Diffusional Mass Trasnport in Metals, Defect and Diffsuion Forum (2001) 71–92.
[9]. Wirth B.D., Odette G.R., Maroudas D., Lucas G.E. Energetics of formation and migration of self-interstitials and self-interstitial clusters in α-iron, J. Nucl. Mater. 244 (1997) 185–194
[10]. Kang C., Wang Q., Shao L. Kinetics of interstitial defects in a -Fe : The effect from uniaxial stress, J. Nucl. Mater. 485 (2017) 159–168.
[11]. Chen Z., Kioussis N., Ghoniem N., Seif D. Strain-field effects on the formation and migration energies of self interstitials in a -Fe from first principles, (2010) 1–10.
[12]. Plimpton S. Fast Parallel Algorithms for Short-Range Molecular Dynamics, J. Comput. Phys. 117 (1995) 1–19.
[13]. Daw M.S., Baskes M.I. Embedded-atom method: Derivation and application to impurities, surfaces, and other defects in metals, Phys. Rev. B. 29 (1984) 6443–6453.
[14]. Mendelev M.I., Han S., Srolovitz D.J., Ackland G.J., Sun D.Y., Asta M. Development of new interatomic potentials appropriate for crystalline and liquid iron, Philos. Mag. 83 (2003) 3977–3994.
[15]. Alexander K.C., Schuh C.A. Visualization and analysis of atomistic simulation data with OVITO – the Open Visualization Tool, Model. Simul. INMATERIALS Sci. Eng. 18 (2010) 7.
[16]. Terentyev D.A., Malerba L., Hou M. Dimensionality of interstitial cluster motion in bcc-Fe, Phys. Rev. B - Condens. Matter Mater. Phys. 75 (2007) 1–13.
[17]. Willaime F., Fu C.C., Marinica M.C., Torre J.D. Stability and mobility of self-interstitials and small interstitial clusters in a -iron : ab initio and empirical potential calculations, 228 (2005) 92–99.
[18]. Anento N., Serra A., Osetsky Y.N. Atomistic study of multimechanism diffusion by selfinterstitial defects in α-Fe, Model. Simul. Mater. Sci. Eng. 18 (2010) 25008.
[19]. JOHNSON R.A. Interstitials and Vacancies in a-Iron, Phys. Rev. 134 (1964) A1329 ~ A1336.
[20]. Kaczmarowski A., Yang S., Szlufarska I., Morgan D. Genetic algorithm optimization of defect clusters in crystalline materials, Comput. Mater. Sci. 98 (2015) 234–244.