Characterization of SEM speckle pattern marking and imaging distortion by digital image correlation

Guery, Adrien; Latourte, Félix; Hild, François; Roux, Stéphane

doi:10.1088/0957-0233/25/1/015401

Cited by 40 publications

(35 citation statements)

References 23 publications

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“…The latter case is the most favorable for kinematic measurements since brightness changes due to out-of plane 5 displacements are essentially prevented. New generations of Scanning Electron Microscopes (SEM) with field emission guns exhibit far less imaging distortions than their predecessors based on Tungsten probe technology [1], and are therefore very well adapted to performing digital image correlation (DIC) measurements [2, 3,4].…”

Section: Introductionmentioning

confidence: 99%

“…Besides, the mechanism of trace generation in EBSD images has not 25 been investigated. An alternative solution is to deposit in situ computer-generated patterns onto the specimen surface by microlithography with a precise knowledge of the reference pattern [3]. Another advantage of the in situ deposition is that the size, shape and thickness of the speckles are easily and precisely controlled by the SEM.…”

Section: Introductionmentioning

confidence: 99%

“…Imaging distortion of 35 SEM has been characterized by DIC [3] on samples with in situ deposited speckles. Slow scan direction error in atomic force microscpy (AFM) has been quantified and corrected [12,13] by capturing two images with orthogonal scan directions.…”

Section: Introductionmentioning

confidence: 99%

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On the use of SEM correlative tools for in situ mechanical tests

et al. 2018

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In situ SEM mechanical tests are key to study crystal plasticity. In particular, imaging and diffraction (EBSD) allow microstructure and surface kinematics to be monitored all along the test. However, to get a full benefit from different modalities, it is necessary to register all images and crystallographic orientation maps from EBSD into the same frame. Different correlative approaches tracking either Pt surface markings, crystal orientations or grain boundaries, allow such registrations to be performed and displacement as well as rotation fields to be measured, a primary information for crystal plasticity identification. However, the different contrasts that are captured in different modalities and unavoidable stage motions also give rise to artifacts that are to be corrected to register the different information onto the same material points. The same image correlation tools reveal very powerful to correct such artifacts. Illustrated by an in situ uniaxial tensile test performed on a bainitic-ferritic steel sample, recent advances in image correlation techniques are reviewed and shown to provide a comprehensive picture of local strain and rotation maps.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the use of SEM correlative tools for in situ mechanical tests

et al. 2018

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“…DIC requires a gray level texture with a dynamic range as large as possible with local contrast variations. In the present case, because the natural texture of the material does not provide enough contrast, a computergenerated random pattern is deposited onto the surface by microlithography [7]. The displacement fields are measured between two consecutive images with a continuous finite element based DIC procedure [8,9].…”

Section: Kinematic Measurements Using Digital Image Correlationmentioning

confidence: 99%

Bridging Kinematic Measurements and Crystal Plasticity Models in Austenitic Stainless Steels

Guery

Latourte

Hild

et al. 2016

Conference Proceedings of the Society for Experimental Mechanics Series

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A digital image correlation procedure is developed to perform kinematic measurements on the surface of 316LN austenitic steel polycrystals. A sequence of images is acquired using a Scanning Electron Microscope (SEM) during in situ tensile tests for various mean grain sizes. To enable digital image correlation, a speckle pattern adapted to the microscopic scale is deposited onto the specimen surface by microlithography. The knowledge of the microstructure at the surface allows for kinematic measurements to be performed using an unstructured finite element mesh consistent with the grain boundaries. The same mesh is then used for the simulation of each tensile test on the experimental microstructure with the measured nodal displacements prescribed as boundary conditions. A crystal plasticity law is considered to simulate the observed strain heterogeneities. An inverse identification method is proposed for the determination of the sought constitutive parameters based on both the local displacement fields and the material homogenized behavior. The parameters associated with isotropic hardening at the grain level are thus identified.

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“…Displacement fields, denoted u k , are then measured using DIC between the acquired images and the reference image of the pattern. Because large rotations are prescribed, the previous DIC formulation has been adapted considering finite transformation kinematics [7]. The partition method consists of considering each displacement field u k as a composition of three transformations, namely, a patterning distortions field υ g , identical for each u k , a rotation of an angle θ k , and an imaging distortions field υ d , assumed to be time-independent.…”

Section: Partition Of Distortionsmentioning

confidence: 99%

Analysis of E-Beam Microlithography and SEM Imaging Distortions

Guery

Latourte

Hild

et al. 2014

Advancement of Optical Methods in Experimental Mechanics, Volume 3

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Surface patterning by e-beam lithography and SEM imaging distortions are studied via digital image correlation. The surface of a stainless steel specimen is marked with a numerically-generated random pattern by microlithography. The global distortions from the reference pattern are first quantified by digital image correlation between the virtual reference pattern and the actual SEM image both in secondary and backscattered electron imaging modes. A second order polynomial basis reveals sufficient to capture most of the distortions. They result from both patterning and imaging techniques. To separate the two contributions without resorting to an external caliper, it is proposed to analyze a series of images of the same patterned surface acquired after rotations of the specimen by different angles. The apparent displacement fields are expressed as a static field, corresponding to the imaging distortion, and another one that rotates together with the specimen. Because large rotations are considered, the problem is nonlinear in the entire set of parameters characterizing each displacement field, but can be solved with an iterative scheme. The obtained patterning distortions appear smaller than those due to imaging on wide field images.

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Characterization of SEM speckle pattern marking and imaging distortion by digital image correlation

Cited by 40 publications

References 23 publications

On the use of SEM correlative tools for in situ mechanical tests

On the use of SEM correlative tools for in situ mechanical tests

Bridging Kinematic Measurements and Crystal Plasticity Models in Austenitic Stainless Steels

Analysis of E-Beam Microlithography and SEM Imaging Distortions

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