Mobility of self-interstitial atom clusters in vanadium, tantalum and copper

Abstract Molecular dynamics (MD) simulations were performed to investigate the mobility of isolated self-interstitial atoms (SIAs) and their clusters in V, Ta and Cu. The migration of an isolated SIA is accompanied by rotation of a dumbbell axis to the close-packed direction of metals. The migration of an SIA cluster strongly depends on its structure. A relatively smaller-size cluster can migrate with simultaneous rotation of the axes of SIA pairs in the cluster to the same close-packed direction, which is the glissile configuration of the cluster. The transformation to the glissile configuration takes place more frequently than the dumbbell rotation of an isolated SIA in V and Ta, while it takes place less frequently in Cu. The smaller cluster can still change its diffusion direction. A greater-size cluster in the bcc metals, on the other hand, has the thermally stable form of densely-packed, parallel crowdions. It migrates without any changes of diffusion direction. The migration behavior of 7-SIAs clusters in Ta was also evaluated as a function of tensile and compressive strains.

[1]  T. D. Rubia,et al.  Progress in the development of a molecular dynamics code for high-energy cascade studies , 1990 .

[2]  T. D. Rubia,et al.  A molecular dynamics simulation study of small cluster formation and migration in metals , 2000 .

[3]  Brian D. Wirth,et al.  Primary damage formation in bcc iron , 1997 .

[4]  M. Finnis,et al.  A simple empirical N-body potential for transition metals , 1984 .

[5]  A. Caro,et al.  The effect of electronic energy loss on the dynamics of thermal spikes in Cu , 1991 .

[6]  James F. Ziegler,et al.  Refined universal potentials in atomic collisions , 1982 .

[7]  Stanislav I Golubov,et al.  Stability and mobility of defect clusters and dislocation loops in metals , 2000 .

[8]  Fei Gao,et al.  The primary damage state in fcc, bcc and hcp metals as seen in molecular dynamics simulations , 2000 .

[9]  D. Maroudas,et al.  Dislocation loop structure, energy and mobility of self-interstitial atom clusters in bcc iron , 2000 .

[10]  A. Serra,et al.  Aspects of microstructure evolution under cascade damage conditions , 1997 .

[11]  H. Trinkaus,et al.  Radiation hardening revisited: role of intracascade clustering , 1997 .

[12]  M. Baskes,et al.  Semiempirical, Quantum Mechanical Calculation of Hydrogen Embrittlement in Metals , 1983 .

[13]  A. B. Lidiard,et al.  Atomic Transport in Solids: List of principal symbols , 1993 .

[14]  A. B. Lidiard,et al.  Atomic transport in solids , 1993 .

[15]  C. English,et al.  Molecular dynamics calculations of displacement threshold energies and replacement collision sequences in copper using a many-body potential , 1992 .