Flow Stress in Submicron BCC Iron Single Crystals: Sample-size-dependent Strain-rate Sensitivity and Rate-dependent Size Strengthening

Huang, Rui; Li, Qingjie; Wang, Zhangjie; Huang, Ling; Li, Ju; Ma, Evan; Shan, Zhiwei

doi:10.1080/21663831.2014.999953

Cited by 35 publications

(18 citation statements)

References 33 publications

(53 reference statements)

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“…MD simulations for h110i-oriented Fe nanopillars predict that the compressive plastic deformation is dominated by twinning 17 or phase transformation, 90 while only dislocation slip has been reported in experiments. [91][92][93] Clearly, there exist quantitative differences between MD simulations and experimental results in plastic deformation of nanopillars.…”

Section: B Twinned Nanopillarsmentioning

confidence: 99%

Size-dependent plastic deformation of twinned nanopillars in body-centered cubic tungsten

Startt

Payne

et al. 2017

Journal of Applied Physics

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Compared with face-centered cubic metals, twinned nanopillars in body-centered cubic (BCC) systems are much less explored partly due to the more complicated plastic deformation behavior and a lack of reliable interatomic potentials for the latter. In this paper, the fault energies predicted by two semi-empirical interatomic potentials in BCC tungsten (W) are first benchmarked against density functional theory calculations. Then, the more accurate potential is employed in large scale molecular dynamics simulations of tensile and compressive loading of twinned nanopillars in BCC W with different cross sectional shapes and sizes. A single crystal, a twinned crystal, and single crystalline nanopillars are also studied as references. Analyses of the stress-strain response and defect nucleation reveal a strong tensioncompression asymmetry and a weak pillar size dependence in the yield strength. Under both tensile and compressive loading, plastic deformation in the twinned nanopillars is dominated by dislocation slip on {110} planes that are nucleated from the intersections between the twin boundary and the pillar surface. It is also found that the cross sectional shape of nanopillars affects the strength and the initial site of defect nucleation but not the overall stress-strain response and plastic deformation behavior. Published by AIP Publishing.

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Section: B Twinned Nanopillarsmentioning

confidence: 99%

Size-dependent plastic deformation of twinned nanopillars in body-centered cubic tungsten

Startt

Payne

et al. 2017

Journal of Applied Physics

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“…Variation of the critical resolved shear stress normalized by the shear modulus versus the sample diameter normalized by the Burgers vector in BCC metals. The original experimental data is reported by Schneider et al [39], Kim et al [40], Han et al [41], Rogne and Thaulow [42], Huang et al [43], and Yilmaz [44] Figure 4. Variation of the critical resolved shear stress normalized by the shear modulus versus the sample diameter normalized by the Burgers vector in BCC metals.…”

Section: Experimental Observationsmentioning

confidence: 99%

Review of Size Effects during Micropillar Compression Test: Experiments and Atomistic Simulations

et al. 2019

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The micropillar compression test is a novel experiment to study the mechanical properties of materials at small length scales of micro and nano. The results of the micropillar compression experiments show that the strength of the material depends on the pillar diameter, which is commonly termed as size effects. In the current work, first, the experimental observations and theoretical models of size effects during micropillar compression tests are reviewed in the case of crystalline metals. In the next step, the recent computer simulations using molecular dynamics are reviewed as a powerful tool to investigate the micropillar compression experiment and its governing mechanisms of size effects.

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“…The dislocation theory discussed above is based on bulk single crystalline and bulk coarse-grained BCC materials. With the decrease of sample/grain size, the type of dislocations controlling plastic deformation processes α-Fe 340 K [108] would change. In single crystalline Mo nanowires, plenty of edge dislocations or dislocations with significant edge components were observed during in situ tensile deformation.…”

Section: Dislocation-mediated Plasticity In Bcc Crystalline Structuresmentioning

confidence: 99%

“…8 shows ultra-large elongation of a single crystalline Mo nanowire with a diameter of 130 nm. Under higher loading stress, the increased density of dislocations could arise from dislocation self-multiplication through cross-slip [100,[106][107][108] in BCC metals. Therefore, except for sample size, the applied stress is another factor determining deformation mechanisms.…”

Section: Size-dependent Yield Strength and Flow Stressmentioning

confidence: 99%

Size effect for achieving high mechanical performance body-centered cubic metals and alloys

2018

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Submicron and nanostructured body-centered cubic (BCC) metals exhibit unusual mechanical performance compared to their bulk coarse-grained counterparts, including high yield strength and outstanding ductility. These properties are important for their applications in micro-, nano-and even atomic-scale devices as well as for their usages as components for enhancing the performances of structural materials. One aspect of the unusual mechanical properties of small-sized BCC metals is closely related to their dimensional confinement. Decreasing the dimensions of single crystalline metals or the grain sizes of polycrystalline metals contributes significantly to the strengthening of the small-sized BCC metals. In the last decade, significant progress has been achieved in understanding the plasticity and deformation behaviors of small-sized BCC metals. This paper aims to provide a comprehensive review on the current understanding of size effects on the plasticity and deformation mechanisms of small-sized BCC metals. The techniques used for in situ characterization of the deformation behavior and mechanical properties of small-sized samples are also presented.

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Flow Stress in Submicron BCC Iron Single Crystals: Sample-size-dependent Strain-rate Sensitivity and Rate-dependent Size Strengthening

Cited by 35 publications

References 33 publications

Size-dependent plastic deformation of twinned nanopillars in body-centered cubic tungsten

Size-dependent plastic deformation of twinned nanopillars in body-centered cubic tungsten

Review of Size Effects during Micropillar Compression Test: Experiments and Atomistic Simulations

Size effect for achieving high mechanical performance body-centered cubic metals and alloys

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