A physically-based constitutive model for bcc crystals with application to polycrystalline tantalum

Nemat‐Nasser, Sia; Okinaka, Tomoo; Ni, Lei

doi:10.1016/s0022-5096(97)00064-1

Cited by 65 publications

(29 citation statements)

References 15 publications

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“…[20,27]). Similar approaches were adopted by Nemat Nasser et al in setting continuum crystal plasticity models for BCC metals [34] and in the work by Naka et al for the thermodynamical treatment of temperature effects in enhancing mobility of screw dislocations through mechanisms such as kink-pair formation [35]. Accordingly, screw dislocations are found to glide through thermally assisted formation of local edge segments whose motion is parallel to the dislocation line of the preexisting screw [36].…”

Section: Introductionmentioning

confidence: 86%

Incipient plasticity of single-crystal tantalum as a function of temperature and orientation

Franke

Alcalá

Dalmau

et al. 2014

Philosophical Magazine

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Section: Introductionmentioning

confidence: 86%

Incipient plasticity of single-crystal tantalum as a function of temperature and orientation

Franke

Alcalá

Dalmau

et al. 2014

Philosophical Magazine

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“…Historically, most crystal plasticity implementations have focused on the quasi-static loading regime, though models have been applied in the intermediate strain rate regime to address dynamic phenomena such as those occurring in Hopkinson bar experiments (Nemat-Nasser et al, 1998), Taylor impact experiments (Schoenfeld, 1998), explosive forming of polycrystalline tantalum liners (Schoenfeld, 1998), and ballistic impact of titanium armor plates (Schoenfeld and Kad, 2002).…”

Section: Background: Modeling Techniquesmentioning

confidence: 99%

Heterogeneous deformation and spall of an extruded tungsten alloy: plate impact experiments and crystal plasticity modeling

Vogler

Clayton

2008

Journal of the Mechanics and Physics of Solids

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information ARL-RP-206 SPONSOR/MONITOR'S ACRONYM(S) 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. SUPPLEMENTARY NOTESA reprint from the Journal of the Mechanics and Physics of Solids, vol. 56, pp. 297-335, 2008. *Sandia National Laboratories, Albuquerque, NM 87185-1181 ABSTRACTThe role of microstructure in the dynamic deformation and fracture of a dual phase, polycrystalline tungsten alloy under highrate impact loading is investigated via experiments and modeling. The material studied consists of pure tungsten crystals embedded in a ductile binder alloy comprised of tungsten, nickel, and iron. The tungsten crystals are elongated in a preferred direction of extrusion during processing. Plate impact tests were conducted on samples oriented either perpendicular or parallel to the extrusion direction. Spatially resolved interferometric data from these tests were used to extract wave propagation behavior and spall strength dependent upon position in the sample microstructure. Finite element simulations of impact and spall in digitally reproduced microstructural geometries were conducted in parallel with the experiments. Finite deformation crystal plasticity theory describes the behavior of the pure tungsten and binder phases, and a stress-and temperature-based cohesive zone model captures fracture at grain and phase boundaries in the microstructure. In results from both experiments and modeling, the grain orientations affect the free-surface velocity profile and spall behavior. Some aspects of distributions of free-surface velocity and spall strength among different microstructure configurations are qualitatively similar between experimental and numerical results, while others are not as a result of differing scales of resolution and modeling assumptions. Following a comparison of experimental and numerical results for different microstructures, intergranular fracture is identified as an important mechanism underlying the spall event. SUBJECT TERMSmicrostructures, tungsten, crystal plasticity, fracture, spall, plate impact, finite elements, probability and statistics AbstractThe role of microstructure in the dynamic deformation and fracture of a dual phase, polycrystalline tungsten alloy under high-rate impact loading is investigated via experiments and modeling. The material studied consists of pure tungsten crystals embedded in a ductile binder alloy comprised of tungsten, nickel, ...

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“…The three families of planes for bcc slip are shown schematically in a cubic unit cell in Figure 1, and the associated plane normals and slip directions are given in Table I. While previous simulations have shown plastic slip to occur in slip systems of all three families, [3] some researchers have found the majority of slip activity to take place in the first two families of slip systems, h111i{110} and h111i{112}. [6,7] The contribution of slip on the {123} planes in bcc systems has been studied previously, [8,9] and while it has been shown that slip on these planes contributes to the overall deformation in bcc materials, one can determine the approximate behavior of many materials systems without computing the exact amount of slip at each point. For some microstructural phenomena, including determining the onset of local plasticity, simulations that use such approximations have been shown to produce reliable results.…”

Section: Introductionmentioning

confidence: 99%

Slip Systems and Initiation of Plasticity in a Body-Centered-Cubic Titanium Alloy

Lewis

Qidwai

Geltmacher

2010

Metall Mater Trans A

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To determine statistically relevant microstructure-yield correlations in three-dimensional (3-D) microstructures, large volumes comprised of many grains must be studied. With the aim of limiting computational loads without reducing the fidelity of the volume being simulated, this work investigates the use of reduced constitutive parameters, specifically the number of available slip systems, to analyze initial plastic flow in the microstructure. This is performed by embedding a 3-D reconstruction of a single-phase beta-Ti microstructure in a finite element (FE) computational model and subjecting it to a number of loading conditions. Three separate singlecrystal plasticity formulations were used for each loading: reduced 12 slip systems (h111i{110} family), reduced 24 slip systems (h111i{110} + h111i{112} families), and full 48 slip systems (h111i{110} + h111i{112} + h111i{123} families). The analysis results show that the 24-slipsystem model accurately predicts the global stress-strain behavior and locations of initial yield under all loadings, with no more than 10 pct error in the spatial description of local state variables compared to the full 48-slip-system model. The 12-slip-system model generally follows the full model predictions and provides an even better cost improvement, but with errors in excess of 40 pct in local descriptions. Computational cost and data reduction are improved by 26 and 53 pct, respectively.

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A physically-based constitutive model for bcc crystals with application to polycrystalline tantalum

Cited by 65 publications

References 15 publications

Incipient plasticity of single-crystal tantalum as a function of temperature and orientation

Incipient plasticity of single-crystal tantalum as a function of temperature and orientation

Heterogeneous deformation and spall of an extruded tungsten alloy: plate impact experiments and crystal plasticity modeling

Slip Systems and Initiation of Plasticity in a Body-Centered-Cubic Titanium Alloy

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