Orientation and rate dependence in high strain-rate compression of single-crystal silicon

Smith, R. F.; Roger, Michel; Rudd, Robert E.; Eggert, J. H.; Bolme, C. A.; Brygoo, S.; Jones, Aaron M.; Collins, G. W.

doi:10.1103/physrevb.86.245204

Cited by 30 publications

(29 citation statements)

References 37 publications

(51 reference statements)

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“…We see that both exhibit elastic compression followed by a plastic softening, with a peak elastic stress of 33 GPa in 100 and lower for 111 . These values are in relatively good agreement with high strain-rate (10 6 − 10 9 1/s) compression experiments in silicon by Smith et al [30] which measured peak elas- tic stresses exceeding twice the Hugoniot Elastic Limits (HELs) measured by Gust and Royce [7]. Extrapolation of the Smith results to MD length and time scale predicts peak elastic stresses in the range from 24 − 33 GPa.…”

Section: Methodssupporting

confidence: 76%

Enhanced densification under shock compression in porous silicon

2014

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Under shock compression, most porous materials exhibit lower densities for a given pressure than that of a full-dense sample of the same material. However, some porous materials exhibit an anomalous, or enhanced, densification under shock compression. We demonstrate a molecular mechanism that drives this behavior. We also present evidence from atomistic simulation that pure silicon belongs to this anomalous class of materials. Atomistic simulations indicate that local shear strain in the neighborhood of collapsing pores nucleates a local solid-solid phase transformation even when bulk pressures are below the thermodynamic phase transformation pressure. This metastable, local, and partial, solid-solid phase transformation, which accounts for the enhanced densification in silicon, is driven by the local stress state near the void, not equilibrium thermodynamics. This mechanism may also explain the phenomenon in other covalently bonded materials.

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Section: Methodssupporting

confidence: 76%

Enhanced densification under shock compression in porous silicon

2014

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“…The first can be identified as the elastic shock front reaching the rear surface, and corresponds to a free surface velocity of 1 kms −1 , which is consistent with a Hugoniot elastic limit of order 9.2 GPa 26 . The cause of the second wave, corresponding here to a stress of 12.5 GPa, has previously been associated with plasticity or a phase change [27][28][29] , although there was no direct evidence of plasticity or a phase change in the diffraction data recorded this experiment. We discuss this finding further below.…”

Section: Resultsmentioning

confidence: 56%

Single Hit Energy-resolved Laue Diffraction

Patel

Suggit

Stubley

et al. 2015

Review of Scientific Instruments

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In-situ white light Laue diffraction has been successfully used to interrogate the structure of single crystal materials undergoing rapid (nanosecond) dynamic compression up to megabar pressures. However, information on strain state accessible via this technique is limited, reducing its applicability for a range of applications. We present an extension to the existing Laue diffraction platform in which we record the photon energy of a subset of diffraction peaks. This allows for a measurement of the longitudinal and transverse strains in-situ during compression. Consequently, we demonstrate measurement of volumetric compression of the unit cell, in addition to the limited aspect ratio information accessible in conventional white light Laue. We present preliminary results for silicon, where only an elastic strain is observed. VISAR measurements show the presence of a two wave structure and measurements show that material downstream of the second wave does not contribute to the observed diffraction peaks, supporting the idea that this material may be highly disordered, or has undergone large scale rotation.

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“…The second plateau is due to the elastic precursor of the diamond ablator propagating through the MgO sample. The peak elastic stress, σ E [16], characterizes the maximum amplitude of uniaxial elastic loading the material can support. We observe elastic stress amplitudes of 3-5.5 GPa for our ~25-45 μm thick samples (figure 3b).…”

Section: Analyses and Discussionmentioning

confidence: 99%