Radiation-induced amorphization of ordered intermetallic compounds CuTi,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CuTi</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>, and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub>

Sabochick, Michael J.; Lam, Nghi Q.

doi:10.1103/physrevb.43.5243

Cited by 136 publications

(42 citation statements)

References 33 publications

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“…20 In particular the mechanical, structural, and thermal properties of the crystalline and amorphous phase compare well with experiments, as indicated in previous studies. [21][22][23] The control of temperature and pressure to achieve isothermal and isobaric conditions is obtained by a Berendsen 24 thermostat and barostat, respectively.…”

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confidence: 86%

Plastic deformation of metallic glasses: Size of shear transformation zones from molecular dynamics simulations

et al. 2006

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Plastic deformation in metallic glasses well below their glass transition temperatures T g occurs spatially heterogeneously within highly localized regions, termed shear transformation zones ͑STZs͒. Yet, their size and the number of atoms involved in a local shear event, remains greatly unclear. With the help of classical molecular dynamics ͑MD͒ computer simulations on plastic deformation of the model glass CuTi during pure shearing, we address this issue by evaluating correlations in atomic-scale plastic displacements, viz. the displacement correlation function. From the correlation length, a universal diameter of about 15 Å, or, equivalently, approximately 120 atoms is derived for a variety of conditions, such as variable strains, strain rates, temperatures, and boundary conditions. The physics of plastic deformation and flow in glassesone of the oldest engineering materials of mankind-is still poorly understood when compared to their crystalline counterparts, and thus has attracted increasing experimental and computational interests during the past decades. [1][2][3][4][5] In particular the highly heterogeneous, cooperative dynamics on multiple time and length scales, 6 and its influence on macroscopic dimensions is still greatly unclear, presumably due to the lack of an atomic-scale picture. This includes the impact on important material properties, such as elastic modulus, fracture behavior, and plastic flow. Adam and Gibbs 7 were the first to invoke the concept of a cooperative rearranging region ͑CRR͒ back in 1965 by proposing clusters that reorganize during shearing. As a main weakness of their treatment, however, they fail to predict a specific cluster size. Subsequent ideas developed by Cohen et al., 8 Spaepen,9 Argon, 10,11 and others describe flow and creep in metallic glasses as activated transformations in intrinsic dynamic heterogeneities, termed shear transformation zones ͑STZs͒. 12These models characterize plastic flow in metallic glasses during shearing as a local event appearing as a spontaneous and cooperative reorganization of individual clusters ͑STZs͒.13-16 As a major problem, however, the size of STZs still remains unclear, in particular for realistic material systems. A first hint to remedy this deficiency was provided by Debenedetti and Stillinger 17 who introduced a potential energy landscape model for the amorphous state and yielding in glasses. Johnson and Samwer 18 extended their treatment and proposed a size of STZs of the order of 100 atoms from energetic considerations.In the present investigations we employ molecular dynamics ͑MD͒ computer simulations to corroborate these predictions and link atomic-scale kinetics and mechanical properties across these length scales by determining the size of STZs as a function of macroscopic quantities. This is accomplished by investigating shear events below T g for the model glass CuTi. Evaluations of the plastic contribution to atomicscale displacements facilitate to identify cooperative motions, as expected in dynamical heterogeneities or ...

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confidence: 86%

Plastic deformation of metallic glasses: Size of shear transformation zones from molecular dynamics simulations

et al. 2006

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“…The disadvantage is that the processes inherent to more energetic ballistic events, such as the effects of shock waves, high displacement densities, and thermal spike on defect production, are not captured. Also not captured are the dependences of phase transformations, such as amorphization in ordered intermetallic compounds [15] on Frenkel pair concentrations or dose. However, such approaches that add Frenkel pairs with time are often limited to smaller simulation cell sizes and are unable to capture the slow evolution of microstructure when Frenkel pairs are added one-byone with time.…”

Section: Methodsmentioning

confidence: 98%

Point defect evolution in Ni, NiFe and NiCr alloys from atomistic simulations and irradiation experiments

et al. 2015

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a b s t r a c tUsing molecular dynamics simulations, we elucidate irradiation-induced point defect evolution in fcc pure Ni, Ni 0.5 Fe 0.5 , and Ni 0.8 Cr 0.2 solid solution alloys. We find that irradiation-induced interstitials form dislocation loops that are of 1/3h1 1 1i{1 1 1}-type, consistent with our experimental results. While the loops are formed in all the three materials, the kinetics of formation is considerably slower in NiFe and NiCr than in pure Ni, indicating that defect migration barriers and extended defect formation energies could be higher in the alloys than pure Ni. As a result, while larger size clusters are formed in pure Ni, smaller and more clusters are observed in the alloys. Vacancy diffusion occurs at relatively higher temperatures than interstitials, and their clustering leads to the formation of stacking fault tetrahedra, consistent with our experiments. The results also show that the surviving Frenkel pairs are composition dependent and are largely Ni dominated.

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“…21,[34][35][36] The ion flux was modeled selecting the impact times randomly in the Poisson distribution 37 such that the average flux corresponded to the one simulated with PIC. The energies were generated in a random distribution corresponding exactly to that obtained from the PIC simulations and the impact positions on the surface were generated randomly within a circle of radius r =3-25 nm.…”

Section: B Simulationsmentioning

confidence: 99%

Mechanism of surface modification in the plasma-surface interaction in electrical arcs

et al. 2010

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Electrical sparks and arcs are plasma discharges that carry large currents and can strongly modify surfaces. This damage usually comes in the form of micrometer-sized craters and frozen-in liquid on the surface. Using a combination of experiments, plasma and atomistic simulation tools, we now show that the observed formation of deep craters and liquidlike features during sparking in vacuum is explained by the impacts of energetic ions, accelerated under the given conditions in the plasma sheath to kiloelectron volt energies, on surfaces. The flux in arcs is so high that in combination with kiloelectron volt energies it produces multiple overlapping heat spikes, which can lead to cratering even in materials such as Cu, where a single heat spike normally does not.

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Radiation-induced amorphization of ordered intermetallic compounds CuTi,CuTi2, andCu4

Cited by 136 publications

References 33 publications

Plastic deformation of metallic glasses: Size of shear transformation zones from molecular dynamics simulations

Plastic deformation of metallic glasses: Size of shear transformation zones from molecular dynamics simulations

Point defect evolution in Ni, NiFe and NiCr alloys from atomistic simulations and irradiation experiments

Mechanism of surface modification in the plasma-surface interaction in electrical arcs

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