ATOMIC DISPLACEMENTS DUE TO POINT DEFECTS IN Ni DILUTE ALLOYS

2003 ◽  
Vol 17 (12) ◽  
pp. 2417-2428 ◽  
Author(s):  
HITESH SHARMA ◽  
S. PRAKASH
Keyword(s):  
Point Defects ◽  
Strain Field ◽  
Static Method ◽  
Embedded Atom Method ◽  
Relaxation Energy ◽  
Dilute Alloys ◽  
Metal Impurities ◽  
Embedded Atom ◽  
Atomic Displacements ◽  
Transition Metal Impurities

The Embedded atom method has been used to investigate the strain field due to substitutional transition metal impurities in Ni. The calculations are carried out in the discrete lattice model of the metal using Kanzaki lattice static method. The results for atomic displacements due to 3d, 4d and 5d impurities (Cu, Pd, Pt and Au) in Ni are given up to 20 NN's of impurity and are compared with the earlier calculations and with the available experimental data. The maximum displacements of 3.6% of 1NN distance are found for NiAu, while the minimum displacements of 0.78% of 1NN distance are found for NiCu alloy respectively. The relaxation energy for Cu are found less than those for Pd, Au and Pt impurities in the Ni host.

Strain field due to transition-metal impurities in Fe

2003 ◽  
Vol 81 (6) ◽  
pp. 847-859 ◽  
Author(s):  
H Sharma ◽  
S Prakash
Keyword(s):  
Transition Metal ◽  
Strain Field ◽  
Nearest Neighbor ◽  
Nearest Neighbors ◽  
Dynamical Matrix ◽  
Relaxation Energy ◽  
Metal Impurities ◽  
Atomic Displacements ◽  
Transition Metal Impurities ◽  
3D Impurities

The Kanzaki lattice static method is used to calculate the strain field due to substitutional transition-metal impurities in Fe. The effective ion–ion interaction potential due to Wills and Harrison is used to calculate the dynamical matrix and the impurity-induced force up to second nearest neighbor of impurity. The atomic displacements due to 3d, 4d, and 5d substitutional transition-metal impurities (Cr, Mn, Ni, Cu, Nb, Mo, W, and Pt ) are calculated up to 24 nearest neighbors. The displacements are minimum for 3d impurities Cr and Mn and maximum for 4d impurity Nb. A similar trend is found in the calculated relaxation energy also. The calculated values are in qualitative agreement with the available experimental data.

scholarly journals Energy calculation of point defects in plutonium by embedded atom method

2010 ◽  
Vol 59 (7) ◽  
pp. 4818
Author(s):  
Hu Wang-Yu ◽  
Yang Jian-Yu ◽  
Ao Bing-Yun ◽  
Wang Xiao-Lin ◽  
Chen Pi-Heng ◽  
...  
Keyword(s):  
Point Defects ◽  
Embedded Atom Method ◽  
Energy Calculation ◽  
Embedded Atom

Molecular-Dynamics Study of the Amorphizatton of CuTi

1989 ◽  
Vol 157 ◽  
Author(s):  
Michael J. Sabochick ◽  
Nghi Q. Lam
Keyword(s):  
Molecular Dynamics ◽  
Pair Correlation ◽  
Embedded Atom Method ◽  
Interatomic Potentials ◽  
Embedded Atom ◽  
Atomic Displacements ◽  
Chemical Disorder ◽  
Radiation Induced ◽  
System Energy ◽  
Dynamics Simulations

ABSTRACTRadiation-induced amorphization of the crystalline compound CuTi was investigated by molecular-dynamics simulations using new interatomic potentials derived from the embedded-atom method. Two different approaches to amorphization were tried: one in which Cu and Ti atoms were randomly exchanged, and another in which Frenkel pairs were introduced at random. The potential energy, volume expansion and pair-correlation function were calculated as functions of chemical disorder and atomic displacements. The results indicate that, although both chemical disordering and point-defect introduction increase the system energy and volume, the presence of Frenkel pairs is essential to trigger the crystalline-to-amorphous transition.

Strain Fields around Dislocation Cores Studied by Analyzing Coordinates of Discrete Atoms

2015 ◽  
Vol 817 ◽  
pp. 712-718
Author(s):  
Yu Fei Shao ◽  
Xin Yang ◽  
Jiu Hui Li ◽  
Xing Zhao
Keyword(s):  
Strain Field ◽  
Strain Tensor ◽  
Dislocation Core ◽  
Dislocation Model ◽  
Embedded Atom Method ◽  
Strain Fields ◽  
Embedded Atom ◽  
Lattice Symmetry ◽  
Dislocation Pair ◽  
Theoretical Predictions

Dislocation core structures in Au and Cu crystals are investigated by means of quasicontinuum simulations combined with the embedded atom method potentials. A dislocation pair in a graphene sheet, which is observed by Warner et al. experimentally, is also analyzed in the present work. The strain fields around these dislocations in Au, Cu, and graphene crystals are calculated by analyzing the coordinates of discrete atoms, which is a strain tensor calculation method proposed by Zimmerman et al., and compared with theoretical predictions based on Foreman dislocation model. It is shown that the strain fields given by Zimmerman theory are completely suitable for describing the dislocation core structures of Au, Cu and graphene crystals. However, compared with the results of Au and Cu, the Zimmerman strain field in the vicinity of graphene dislocation core is a little less accurate, possibly due to the effect of lattice symmetry of graphene, which needs to be clarified in the future study.

Energy Levels of Point Defects in Perovskite Oxides

1994 ◽  
Vol 361 ◽  
Author(s):  
J. Robertson ◽  
W. L. Warren
Keyword(s):  
Transition Metal ◽  
Band Structure ◽  
Band Gap ◽  
Point Defects ◽  
Energy Levels ◽  
Perovskite Oxides ◽  
Atomic Electron ◽  
Metal Impurities ◽  
Transition Metal Impurities ◽  
Trapped Electron

ABSTRACTThe band structure and energy levels of defects in BaTi3, PbTiO3 and PbZrO3 are calculated and compared. The band gap of Pb(Zr,Ti)O3 varies little because the band edges are formed of Pb 6s and 6p states. The charged Ti and O vacancies are found to be shallow. Transition metal impurities at the B site are found to give rise to numerous charge states because of their high intra-atomic electron repulsion. The levels of Cr4+, Fe4+ and Co4+ lie near midgap. Ti3+ trapped electron centers become deep at higher Zr contents in PZT.

Sign in / Sign up

Export Citation Format

Share Document