Point Defect Clusters and Dislocations in FIB Irradiated Nanocrystalline Aluminum Films: An Electron Tomography and Aberration-Corrected High-Resolution ADF-STEM Study

Idrissi, Hosni; Turner, Stuart; Mitsuhara, Masatoshi; Wang, Binjie; Hata, Satoshi; Coulombier, Michaël; Raskin, J.-P.; Pardoen, Thomas; Tendeloo, Gustaaf Van; Schryvers, D.

doi:10.1017/s143192761101213x

Cited by 33 publications

(23 citation statements)

References 40 publications

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“…ADF-STEM imaging was performed using an ADF collection inner semi-angle optimized to allow both diffraction and massthickness contrast to contribute to the image formation in order to make defects easily visible. 19 The close packing of the diamond grains can be seen in the plan-view image in Fig. 1a.…”

Section: 12mentioning

confidence: 88%

Local boron environment in B-doped nanocrystalline diamond films

Turner

Janssens

et al. 2012

Nanoscale

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Thin films of heavily B-doped nanocrystalline diamond (B:NCD) have been investigated by a combination of high resolution annular dark field scanning transmission electron microscopy and spatially resolved electron energy-loss spectroscopy performed on a state-of-the-art aberration corrected instrument to determine the B concentration, distribution and the local B environment. Concentrations of $1 to 3 at.% of boron are found to be embedded within individual grains. Even though most NCD grains are surrounded by a thin amorphous shell, elemental mapping of the B and C signal shows no preferential embedding of B in these amorphous shells or in grain boundaries between the NCD grains, in contrast with earlier work on more macroscopic superconducting polycrystalline Bdoped diamond films. Detailed inspection of the fine structure of the boron K-edge and comparison with density functional theory calculated fine structure energy-loss near-edge structure signatures confirms that the B atoms present in the diamond grains are substitutional atoms embedded tetrahedrally into the diamond lattice.

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Section: 12mentioning

confidence: 88%

Local boron environment in B-doped nanocrystalline diamond films

Turner

Janssens

et al. 2012

Nanoscale

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“…Recent experiments confirmed formation of a dislocation network [16] in Au nanoparticles and dislocation loops in the Al thin film [17] at fluences typical for focused ion beam (FIB) milling. TEM observation of as-fabricated Al nanopillars revealed the formation of nm-sized dislocation loops [18].…”

Section: Introductionmentioning

confidence: 93%

“…TEM observation of as-fabricated Al nanopillars revealed the formation of nm-sized dislocation loops [18]. According to [17], the dislocation loops formed by a high energy Ga ? ion impact in Al at room temperature are most likely of the interstitial type.…”

Section: Introductionmentioning

confidence: 99%

On the fabrication of micro- and nano-sized objects: the role of interstitial clusters

et al. 2018

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Ion-induced bending phenomena were studied in free-standing nano-sized Al cantilevers with thicknesses in the range of 89-200 nm. The objective is to present a predictive and useful model for the fabrication of micro-and nanosized specimens. Samples were irradiated in a Tescan Lyra dual beam system with 30 kV Ga ? ions normal to the sample surface up to a maximum fluence of * 2 9 10 21 m -2 . Irrespective of thickness, all samples bent initially away from the Ga ? beam; as irradiation proceeded, the bending direction was reversed. The Al cantilever bending behavior is discussed in terms of depth-dependent volume change due to implanted Ga atoms, radiation-induced point defects and interstitial clusters. A kinetic model is designed which is based on a set of rate equations for concentrations of vacancies, interstitial atoms, Ga atoms and clusters of interstitial atoms. The bending crossover is explained by the formation of sessile interstitial clusters in a zone beyond the Ga ? penetration range.Model predictions agree with our experimental findings.

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“…The loading axis was along the ½111 crystallographic direction of the face-centered cubic (FCC) Al crystal, and the beam direction was close to the [110] zone axis, as confirmed by the selected area electron diffraction pattern. Two types of dislocations were identified in the as-fabricated aluminum crystal: dislocation lines inherited from the bulk crystal or generated during the fabrication process and Frank dislocation loops introduced by ion beam irradiation during FIB cutting, which usually occur in the regions close to the free surface (19). The initial densities of dislocation lines and dislocation loops in the as-fabricated crystal specimen were measured to be ∼2.0 × 10 13 m -2 and 4.6 × 10 13 m -2 , respectively (Fig.…”

Section: Significancementioning

confidence: 99%

Cyclic deformation leads to defect healing and strengthening of small-volume metal crystals

Wang

Cui

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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When microscopic and macroscopic specimens of metals are subjected to cyclic loading, the creation, interaction, and accumulation of defects lead to damage, cracking, and failure. Here we demonstrate that when aluminum single crystals of submicrometer dimensions are subjected to low-amplitude cyclic deformation at room temperature, the density of preexisting dislocation lines and loops can be dramatically reduced with virtually no change of the overall sample geometry and essentially no permanent plastic strain. This "cyclic healing" of the metal crystal leads to significant strengthening through dramatic reductions in dislocation density, in distinct contrast to conventional cyclic strain hardening mechanisms arising from increases in dislocation density and interactions among defects in microcrystalline and macrocrystalline metals and alloys. Our real-time, in situ transmission electron microscopy observations of tensile tests reveal that pinned dislocation lines undergo shakedown during cyclic straining, with the extent of dislocation unpinning dependent on the amplitude, sequence, and number of strain cycles. Those unpinned mobile dislocations moving close enough to the free surface of the thin specimens as a result of such repeated straining are then further attracted to the surface by image forces that facilitate their egress from the crystal. These results point to a versatile pathway for controlled mechanical annealing and defect engineering in submicrometer-sized metal crystals, thereby obviating the need for thermal annealing or significant plastic deformation that could cause change in shape and/or dimensions of the specimen.fatigue | dislocation motion | pristine materials | yield strength | cyclic mechanical healing

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Point Defect Clusters and Dislocations in FIB Irradiated Nanocrystalline Aluminum Films: An Electron Tomography and Aberration-Corrected High-Resolution ADF-STEM Study

Cited by 33 publications

References 40 publications

Local boron environment in B-doped nanocrystalline diamond films

Local boron environment in B-doped nanocrystalline diamond films

On the fabrication of micro- and nano-sized objects: the role of interstitial clusters

Cyclic deformation leads to defect healing and strengthening of small-volume metal crystals

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