期刊
PHYSICAL REVIEW MATERIALS
卷 5, 期 8, 页码 -出版社
AMER PHYSICAL SOC
DOI: 10.1103/PhysRevMaterials.5.083603
关键词
-
资金
- Science Undergraduate Laboratory Internships program from the Department of Energy Office of Science
- Illinois Scholars Undergraduate Research Program
- Department of Energy National Nuclear Security Administration Stewardship Science Graduate Fellowship [DE-NA0003960]
- Laboratory Directed Research and Development program of Los Alamos National Laboratory [20150557ER]
- National Nuclear Security Administration of U.S. Department of Energy [89233218CNA000001]
- National Science Foundation [OCI-0725070, ACI-1238993]
- state of Illinois
This study used the Parallel Trajectory Splicing (ParSplice) method to simulate dislocation climb in nickel and focused on investigating the dominant mechanism for vacancy absorption by jogs. The results suggest that the main mechanism for vacancy absorption by jogs is biased diffusion to the dislocation core followed by fast pipe diffusion to the jog.
The mechanical behavior of materials operating under high temperatures is strongly influenced by creep mechanisms such as dislocation climb, which is controlled by the diffusion of vacancies. However, atomistic simulations of these mechanisms have traditionally been impractical due to the long time scales required. To overcome these time scale challenges, we use Parallel Trajectory Splicing (ParSplice), an accelerated molecular dynamics method, to simulate dislocation climb in nickel. We focus on modeling the activity of a vacancy near a jog on an edge dislocation in order to observe vacancy pipe diffusion and vacancy absorption at the jog. From rigorously constructed trajectories encompassing more than 2000 vacancy absorption events over a simulation time of more than 4 mu s at 900 K, a comprehensive sampling of available atomistic mechanisms is collated and analyzed further with molecular statics calculations. We estimate average rates for pipe diffusion and vacancy absorption into the jog using data from the dynamic and static calculations, finding very good agreement. Our results strongly suggest that the dominant mechanism for vacancy absorption by jogs is via biased diffusion to the dislocation core followed by fast pipe diffusion to the jog.
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