Orientation-dependent response of defective Tantalum single crystals

Tramontina, Diego; Ruestes, Carlos J.; Tang, Yizhe; Bringa, Eduardo M.

doi:10.1016/j.commatsci.2014.03.069

Cited by 24 publications

(16 citation statements)

References 55 publications

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“…Liu et al [ 15 ] used the extended Finnis-Sinclair (EFS) potential and investigated thermal EOS as well as melting properties of Ta at pressures up to 400 GPa. Besides, Tramontina et al [ 16 , 17 ] studied the effects of crystal orientation on plasticity mechanisms at high pressures. They also discussed the influence of shock strength and shock rise time on their microstructures.…”

Section: Introductionmentioning

confidence: 99%

Temperature and Pressure Dependences of the Elastic Properties of Tantalum Single Crystals Under <100> Tensile Loading: A Molecular Dynamics Study

Kang

Fan

et al. 2018

Nanoscale Res Lett

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Atomistic simulations are capable of providing insights into physical mechanisms responsible for mechanical properties of the transition metal of Tantalum (Ta). By using molecular dynamics (MD) method, temperature and pressure dependences of the elastic properties of Ta single crystals are investigated through <100> tensile loading. First of all, a comparative study between two types of embedded-atom method (EAM) potentials is made in term of the elastic properties of Ta single crystals. The results show that Ravelo-EAM (Physical Review B, 2013, 88: 134101) potential behaves well at different hydrostatic pressures. Then, the MD simulation results based on the Ravelo-EAM potential show that Ta will experience a body-centered-cubic (BCC) to face-centered-cubic (FCC) phase transition before fracture under <100> tensile loading at 1 K temperature, and model size and strain rate have no obvious effects on tensile behaviors of Ta. Next, from the simulation results at the system temperature from 1 to 1500 K, it can be derived that the elastic modulus of E100 linearly decrease with the increasing temperature, while the yielding stress decrease with conforming a quadratic polynomial formula. Finally, the pressure dependence of the elastic properties is performed from 0 to 140 GPa and the observations show that the elastic modulus increases with the increasing pressure overall.

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Section: Introductionmentioning

confidence: 99%

Temperature and Pressure Dependences of the Elastic Properties of Tantalum Single Crystals Under <100> Tensile Loading: A Molecular Dynamics Study

Kang

Fan

et al. 2018

Nanoscale Res Lett

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“…The first is characterized by a combination of dislocation slip and deformation twinning of the types [111](211) and [111](211). That twinning of this kind operates in rapidly-strained [011] Ta is well-known, having been extensively observed in MD 22,27,49,58,65,66 and in experiment, both ex-post-facto [66][67][68] and, more recently, in-situ via time-resolved XRD. 22,27 The deformation twins nucleate first, and are then partially replaced by the full dislocations, which are able to accommodate the same shear strain as the twins without the large energy cost associated with their surfaces.…”

Section: A Single Crystal Responsementioning

confidence: 83%

Molecular dynamics simulations of grain interactions in shock-compressed highly textured columnar nanocrystals

Heighway

McGonegle

Park

et al. 2019

Phys. Rev. Materials

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While experimental and computational studies abound demonstrating the diverse range of phenomena caused by grain interactions under quasistatic loading conditions, far less attention has been given to these interactions under the comparatively dramatic conditions of shock compression. The consideration of grain interactions is essential within the context of contemporary shock-compression experiments that exploit the distinctive x-ray diffraction patterns of highly textured (and therefore strongly anisotropic) targets in order to interrogate local structural evolution. We present here a study of grain interaction effects in shock-compressed, body-centered cubic tantalum nanocrystals characterized by a columnar geometry and a strong fiber texture using large-scale molecular dynamics simulations. Our study reveals that contiguous grains deform cooperatively in directions perpendicular to the shock, driven by the gigapascal-scale stress gradients induced over their boundaries by the uniaxial compression, and in so doing are able to reach a state of reduced transverse shear stress. We compare the extent of this relaxation for two different columnar geometries (distinguished by their square or hexagonal cross-sections), and quantify the attendant change in the transverse elastic strains. We further show that cooperative deformation is able to replace ordinary plastic deformation mechanisms at lower shock pressures, and, under certain conditions, activate new mechanisms at higher pressures.

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“…Ta was modeled using the embedded-atom method potential developed by Ravelo et al [4], which has been successfully used to examine ramp-wave strength and shock-induced plasticity in high pressure regimes [10,11]. Propagating ramp compression and release waves were imposed by moving an infinite-mass momentum mirror piston along the x-axis, while periodic boundary conditions were enforced on the transverse (y and z) directions.…”

Section: Methodsmentioning

confidence: 99%

Molecular scale study of the plastic response of tantalum under ramp compression and release

Moore

Lim

Brown

et al. 2018

AIP Conference Proceedings

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Abstract. There is significant uncertainty about the relationships between microstructure, plasticity mechanisms, and strength in high pressure and high strain-rate conditions. Using molecular dynamics simulations of propagating ramp compression and release waves, we examine strength and plasticity in [100] single crystalline and nanocrystalline tantalum. We find that the strength response of Ta under dynamic loading can be separated into two categories: the elastic/plastic transition and steady plastic flow regimes. The single crystalline and nanocrystalline Ta display significantly different strengths in the elastic/plastic transition regime. Surprisingly, the two forms of Ta exhibit similar strengths in the steady plastic flow regime despite their differences in microstructure and plastic deformation mechanisms. We also find that the transition from the elastic/plastic regime to the steady plastic flow regime is accompanied by either dislocation density reaching saturation or twin nucleation and growth. Twinning only occurs when the dislocation density has not reached saturation before transitioning into the steady plastic flow regime. The nucleated twins that formed during the transition to steady plastic flow shrink and disappear as dislocation density increases to its saturation value.

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Orientation-dependent response of defective Tantalum single crystals

Cited by 24 publications

References 55 publications

Temperature and Pressure Dependences of the Elastic Properties of Tantalum Single Crystals Under <100> Tensile Loading: A Molecular Dynamics Study

Temperature and Pressure Dependences of the Elastic Properties of Tantalum Single Crystals Under <100> Tensile Loading: A Molecular Dynamics Study

Molecular dynamics simulations of grain interactions in shock-compressed highly textured columnar nanocrystals

Molecular scale study of the plastic response of tantalum under ramp compression and release

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