Dynamics and Stability of Subsonic Crowdion Clusters in 2D Morse Crystal
- PDF / 1,021,888 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 45 Downloads / 171 Views
AND LIQUIDS
Dynamics and Stability of Subsonic Crowdion Clusters in 2D Morse Crystal1 E. A. Korznikovaa,b,c,*, I. A. Shepelevc, A. P. Chetverikovc, S. V. Dmitrieva,c,d, S. Yu. Fominb, and Kun Zhoue a
Institute for Metals Superplasticity Problems, Russian Academy of Sciences, Ufa, 450001 Russia b Ufa State Aviation Technical University, Ufa, 450008 Russia c Saratov Chernyshevsky National Research State University, Saratov, 410012 Russia d National Research Tomsk State University, Tomsk, 634050 Russia e School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798 Singapore * e-mail: [email protected] Received May 23, 2018
Abstract—Recently, the concept of supersonic N-crowdions was offered. In molecular dynamics simulations, they can be excited by initial kick of N neighboring atoms located in one close-packed atomic row along this row. In the present study, in 2D Morse crystal, we apply initial kick to M neighboring atoms located in neighboring close-packed atomic rows along these rows. This way, we initiate crowdion clusters called subsonic Mcrowdions. It is well known that static 1-crowdion in 2D Morse lattice is unstable; as a result, the interstitial atom leaves the close-packed atomic row and becomes immobile. However, we show that 1-crowdion moving with sufficiently large subsonic velocity remains in the close-packed atomic row. Crowdion clusters with M equal to or greater than 2 appear to be stable even at rest, with growing M transforming into prismatic dislocation loops. It is important to note that stable subsonic M-crowdions (M > 1) remain mobile and they can carry interstitial atoms over long distances. DOI: 10.1134/S1063776118120063
1. INTRODUCTION It is widely known that different types of point defects such as vacancies, interstitials and their complexes, play a very important role in mass transfer in crystals and their contribution largely increases in non-equilibrium conditions caused by external impacts, e.g., plastic deformation, irradiation, heat treatment, etc. [1–15]. Crowdion is a sort of interstitial atom when an extra atom is positioned in a closepacked atomic row. For the first time the concept of crowdion was introduced by Paneth in 1950 in the interpretation of defect annihilation peaks of calorimetric curve [16]. Later investigations have revealed that crowdion mechanism can contribute significantly to the mass-transfer during high-temperature crack healing [4] and diffusion on some strained surfaces may be mediated by the formation and motion of surface crowdions [17]. In [18] it was shown that diffusion of crowdions is not described by Arrhenius law and at elevated temperatures the diffusion coefficient varies linearly as a function of absolute temperature. Crowdions can move along a close-packed atomic row 1 The article was translated by the authors.
with subsonic or supersonic velocity. In the former case they are localized typically on a half a dozen of atoms, while in the latter case they are sharply localized
Data Loading...
