Molecular-dynamics simulation of electron-irradiation-induced amorphization of NiZr[sub 2]

Journal Article · Thu Jul 01 04:00:00 EDT 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.42· OSTI ID:6344788

Devanathan, R ^[1]; Lam, N Q; Okamoto, P R ^[2]; Meshii, M ^[3]

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1. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States)
2. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
3. Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States)

We have used molecular-dynamics simulations to examine electron-irradiation-induced amorphization of the ordered intermetallic compound NiZr[sub 2]. The principal effects of irradiation by MeV electrons, namely chemical disorder and Frenkel-pair generation, were simulated in two separate processes: Chemical disorder was created by exchanging randomly selected Ni and Zr atoms, and Frenkel pairs were introduced by removing atoms at random from their sites and introducing them into interstitial positions. The interactions between the atoms were governed by embedded-atom potentials. During the simulation, the potential energy, volume, radial distribution function, elastic constants, and mean-square atomic displacement were calculated as functions of damage dose. In addition, the structure of the system was characterized by diffraction patterns obtained with the use of the multislice method in conjunction with the simulation. Our results indicate that both random atom exchanges and Frenkel-pair introduction can amorphize NiZr[sub 2]. At the critical dose of about 0.16 dpa (displacements per atom), the energy and volume attained values corresponding to the quenched liquid and the system became elastically isotropic. Moreover, the variation of the average shear elastic constant with mean-square atomic displacement, following isothermal disorder and isobaric heating, provides evidence in favor of a unified description of amorphization and melting. The results obtained in the present work are in agreement with experimental observations.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6344788
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 48:1; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360106* -- Metals & Alloys-- Radiation Effects
ALLOYS
AMORPHOUS STATE
BEAMS
COMPUTERIZED SIMULATION
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTRON BEAMS
ENERGY RANGE
FRENKEL DEFECTS
INTERMETALLIC COMPOUNDS
LEPTON BEAMS
MEV RANGE
NICKEL COMPOUNDS
PARTICLE BEAMS
PHYSICAL RADIATION EFFECTS
POINT DEFECTS
RADIATION EFFECTS
SIMULATION
TRANSITION ELEMENT COMPOUNDS
VACANCIES
ZIRCONIUM COMPOUNDS