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  1. Book ; Online: Plasticity, localization, and damage in ferritic-pearlitic steel studied by nanoscale digital image correlation

    Vermeij, Tijmen / Hoefnagels, Johan

    2021  

    Abstract: The evolution of deformation from plasticity to localization to damage is investigated in ferritic-pearlitic steel through nanometer-resolution microstructure-correlated SEM-DIC (u-DIC) strain mapping, enabled through highly accurate microstructure-to- ... ...

    Abstract The evolution of deformation from plasticity to localization to damage is investigated in ferritic-pearlitic steel through nanometer-resolution microstructure-correlated SEM-DIC (u-DIC) strain mapping, enabled through highly accurate microstructure-to-strain alignment. We reveal the key plasticity mechanisms in ferrite and pearlite as well as their evolution into localization and damage and their relation to the microstructural arrangement. Notably, two contrasting mechanisms were identified that control whether damage initiation in pearlite occurs and, through connection of localization hotspots in ferrite grains, potentially results in macroscale fracture: (i) cracking of pearlite bridges with relatively clean lamellar structure by brittle fracture of cementite lamellae due to build-up of strain concentrations in nearby ferrite, versus (ii) large plasticity without damage in pearlite bridges with a more "open", chaotic pearlite morphology, which enables plastic percolation paths in the interlamellar ferrite channels. Based on these insights, recommendations for damage resistant ferritic-pearlitic steels are proposed.

    Comment: 10 pages, 4 figures
    Keywords Condensed Matter - Materials Science
    Subject code 621 ; 669
    Publishing date 2021-04-23
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Book ; Online: Crystallographic slip activity fields identified automatically from DIC data, even for intersecting, diffuse and cross slip

    Vermeij, Tijmen / Peerlings, Ron / Geers, Marc / Hoefnagels, Johan

    2022  

    Abstract: Crystallographic slip system identification methods are widely employed to characterize the fine scale deformation of metals. While powerful and widely employed, they usually rely on the occurrence of discrete slip bands with clear slip traces and ... ...

    Abstract Crystallographic slip system identification methods are widely employed to characterize the fine scale deformation of metals. While powerful and widely employed, they usually rely on the occurrence of discrete slip bands with clear slip traces and struggle when mechanisms such as cross-slip, curved slip, diffuse slip and/or intersecting slip occur. This paper proposes a novel slip system identification framework in which the measured displacement gradient fields (from Digital Image Correlation) are matched with the kinematics of one or multiple combined slip systems. To identify the amounts of slip that conform to the measured kinematics, an optimization problem is solved for every datapoint individually, resulting in a slip activity field for every considered slip system. The identification framework is demonstrated and validated on an HCP virtual experiment, for discrete and diffuse slip, incorporating 24 slip systems. Experimental case studies on FCC and BCC metals show how full-field identification of discrete slip, diffuse slip and cross-slip becomes feasible, even when considering 48 slip systems for BCC. Moreover, the methodology is extended into a dedicated cross-slip identification method, which directly yields the orientation of the local slip plane trace orientation, purely based on the measured kinematics and on one or two chosen slip directions. For even more challenging cases revealing a persistent uncertainty in the slip identification, a two-step identification approach can be employed, as is demonstrated on a highly challenging HCP virtual experiment.

    Comment: submitted for publication; 22 pages, 11 figures
    Keywords Condensed Matter - Materials Science
    Subject code 621
    Publishing date 2022-07-26
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Book ; Online: A Nanomechanical Testing Framework Yielding Front&Rear-Sided, High-Resolution, Microstructure-Correlated SEM-DIC Strain Fields

    Vermeij, Tijmen / Verstijnen, Jorn / Cantador, Tim Ramirez y / Blaysat, Benoit / Neggers, Jan / Hoefnagels, Johan

    2022  

    Abstract: The continuous development of new multiphase alloys with improved mechanical properties requires quantitative microstructure-resolved observation of the nanoscale deformation mechanisms at, e.g., multiphase interfaces. This calls for a combinatory ... ...

    Abstract The continuous development of new multiphase alloys with improved mechanical properties requires quantitative microstructure-resolved observation of the nanoscale deformation mechanisms at, e.g., multiphase interfaces. This calls for a combinatory approach beyond advanced testing methods such as microscale strain mapping on bulk material and micrometer sized deformation tests of single grains. We propose a nanomechanical testing framework that has been carefully designed to integrate several state-of-the-art testing and characterization methods: (i) well-defined nano-tensile testing of carefully selected and isolated multiphase specimens, (ii) front&rear-sided SEM-EBSD microstructural characterization combined with front&rear-sided in-situ SEM-DIC testing at very high resolution enabled by a recently developed InSn nano-DIC speckle pattern, (iii) optimized DIC strain mapping aided by application of SEM scanning artefact correction and DIC deconvolution for improved spatial resolution, (iv) a novel microstructure-to-strain alignment framework to deliver front&rear-sided, nanoscale, microstructure-resolved strain fields, and (v) direct comparison of microstructure, strain and SEM-BSE damage maps in the deformed configuration. Demonstration on a micrometer-sized dual-phase steel specimen, containing an incompatible ferrite-martensite interface, shows how the nanoscale deformation mechanisms can be unraveled. Discrete lath-boundary-aligned martensite strain localizations transit over the interface into diffuse ferrite plasticity, revealed by the nanoscale front&rear-sided microstructure-to-strain alignment and optimization of DIC correlations. The proposed framework yields front&rear-sided aligned microstructure and strain fields providing 3D interpretation of the deformation and opening new opportunities for unprecedented validation of advanced multiphase simulations.

    Comment: Accepted in Experimental Mechanics
    Keywords Physics - Applied Physics ; Condensed Matter - Materials Science
    Subject code 669
    Publishing date 2022-01-18
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Book ; Online: One-step deposition of nano-to-micron-scalable, high-quality DIC patterns for high-strain in-situ multi-microscopy testing

    Hoefnagels, Johan / van Maris, Marc / Vermeij, Tijmen

    2019  

    Abstract: Digital Image Correlation (DIC) is of vital importance in the field of experimental mechanics, yet, producing suitable DIC patterns for challenging in-situ mechanical tests remains challenging, especially for ultra-fine patterns, despite the large number ...

    Abstract Digital Image Correlation (DIC) is of vital importance in the field of experimental mechanics, yet, producing suitable DIC patterns for challenging in-situ mechanical tests remains challenging, especially for ultra-fine patterns, despite the large number of patterning techniques in the literature. Therefore, we propose a simple, flexible, one-step technique (only requiring a conventional deposition machine) to obtain scalable, high-quality, robust DIC patterns, suitable for a range of microscopic techniques, by deposition of a low melting temperature solder alloy in so-called 'island growth' mode, without elevating the substrate temperature. Proof of principle is shown by (near-)room-temperature deposition of InSn patterns, yielding highly dense, homogeneous DIC patterns over large areas with a feature size that can be tuned from as small as 10nm to 2um and with control over the feature shape and density by changing the deposition parameters. Pattern optimization, in terms of feature size, density, and contrast, is demonstrated for imaging with atomic force microscopy, scanning electron microscopy (SEM), optical microscopy and profilometry. Moreover, the performance of the InSn DIC patterns and their robustness to large deformations is validated in two challenging case studies of in-situ micro-mechanical testing: (i) self-adaptive isogeometric digital height correlation of optical surface height profiles of a coarse, bimodal InSn pattern providing microscopic 3D deformation fields (illustrated for delamination of aluminum interconnects on a polyimide substrate) and (ii) DIC on SEM images of a much finer InSn pattern allowing quantification of high strains near fracture locations (illustrated for rupture of a Fe foil). As such, the high controllability, performance and scalability of the DIC patterns offers a promising step towards more routine DIC-based in-situ micro-mechanical testing.

    Comment: submitted for publication
    Keywords Physics - Applied Physics ; Condensed Matter - Materials Science
    Subject code 669
    Publishing date 2019-04-26
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article: A Platform for Mechano(-Electrical) Characterization of Free-Standing Micron-Sized Structures and Interconnects.

    Savov, Angel / Joshi, Shivani / Shafqat, Salman / Hoefnagels, Johan / Louwerse, Marcus / Stoute, Ronald / Dekker, Ronald

    Micromachines

    2018  Volume 9, Issue 1

    Abstract: A device for studying the mechanical and electrical behavior of free-standing micro-fabricated metal structures, subjected to a very large deformation, is presented in this paper. The free-standing structures are intended to serve as interconnects in ... ...

    Abstract A device for studying the mechanical and electrical behavior of free-standing micro-fabricated metal structures, subjected to a very large deformation, is presented in this paper. The free-standing structures are intended to serve as interconnects in high-density, highly stretchable electronic circuits. For an easy, damage-free handling and mounting of these free-standing structures, the device is designed to be fabricated as a single chip/unit that is separated into two independently movable parts after it is fixed in the tensile test stage. Furthermore, the fabrication method allows for test structures of different geometries to be easily fabricated on the same substrate. The utility of the device has been demonstrated by stretching the free-standing interconnect structures in excess of 1000% while simultaneously measuring their electrical resistance. Important design considerations and encountered processing challenges and their solutions are discussed in this paper.
    Language English
    Publishing date 2018-01-18
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2620864-7
    ISSN 2072-666X
    ISSN 2072-666X
    DOI 10.3390/mi9010039
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Correction of scan line shift artifacts in scanning electron microscopy: An extended digital image correlation framework.

    Maraghechi, Siavash / Hoefnagels, Johan P M / Peerlings, Ron H J / Geers, Marc G D

    Ultramicroscopy

    2018  Volume 187, Page(s) 144–163

    Abstract: High resolution scanning electron microscopy (HR-SEM) is nowadays very popular for different applications in different fields. However, SEM images may exhibit a considerable amount of imaging artifacts, which induce significant errors if the images are ... ...

    Abstract High resolution scanning electron microscopy (HR-SEM) is nowadays very popular for different applications in different fields. However, SEM images may exhibit a considerable amount of imaging artifacts, which induce significant errors if the images are used to measure geometrical or kinematical fields. This error is most pronounced in case of full field deformation measurements, for instance by digital image correlation (DIC). One family of SEM artifacts result from positioning errors of the scanning electron beam, creating artifactual shifts in the images perpendicular to the scan lines (scan line shifts). This leads to localized distortions in the displacement fields obtained from such images, by DIC. This type of artifacts is corrected here using global DIC (GDIC). A novel GDIC framework, considering the nonlinear influence of artifacts in the imaging system, is introduced for this purpose. Using an enriched regularization in the global DIC scheme, based on an error function, the scan line shift artifacts are captured and eliminated. The proposed methodology is demonstrated in virtually generated and deformed images as well as real SEM micrographs. The results confirm the proper detection and elimination of this type of SEM artifacts.
    Language English
    Publishing date 2018
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1479043-9
    ISSN 1879-2723 ; 0304-3991
    ISSN (online) 1879-2723
    ISSN 0304-3991
    DOI 10.1016/j.ultramic.2018.01.002
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Ultra-Stretchable Interconnects for High-Density Stretchable Electronics.

    Shafqat, Salman / Hoefnagels, Johan P M / Savov, Angel / Joshi, Shivani / Dekker, Ronald / Geers, Marc G D

    Micromachines

    2017  Volume 8, Issue 9

    Abstract: The exciting field of stretchable electronics (SE) promises numerous novel applications, particularly in-body and medical diagnostics devices. However, future advanced SE miniature devices will require high-density, extremely stretchable interconnects ... ...

    Abstract The exciting field of stretchable electronics (SE) promises numerous novel applications, particularly in-body and medical diagnostics devices. However, future advanced SE miniature devices will require high-density, extremely stretchable interconnects with micron-scale footprints, which calls for proven standardized (complementary metal-oxide semiconductor (CMOS)-type) process recipes using bulk integrated circuit (IC) microfabrication tools and fine-pitch photolithography patterning. Here, we address this combined challenge of microfabrication with extreme stretchability for high-density SE devices by introducing CMOS-enabled, free-standing, miniaturized interconnect structures that fully exploit their 3D kinematic freedom through an interplay of buckling, torsion, and bending to maximize stretchability. Integration with standard CMOS-type batch processing is assured by utilizing the Flex-to-Rigid (F2R) post-processing technology to make the back-end-of-line interconnect structures free-standing, thus enabling the routine microfabrication of highly-stretchable interconnects. The performance and reproducibility of these free-standing structures is promising: an elastic stretch beyond 2000% and ultimate (plastic) stretch beyond 3000%, with <0.3% resistance change, and >10 million cycles at 1000% stretch with <1% resistance change. This generic technology provides a new route to exciting highly-stretchable miniature devices.
    Language English
    Publishing date 2017-09-13
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2620864-7
    ISSN 2072-666X
    ISSN 2072-666X
    DOI 10.3390/mi8090277
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  8. Article: From Fibrils to Toughness: Multi-Scale Mechanics of Fibrillating Interfaces in Stretchable Electronics.

    van der Sluis, Olaf / Vermeij, Tijmen / Neggers, Jan / Vossen, Bart / van Maris, Marc / Vanfleteren, Jan / Geers, Marc / Hoefnagels, Johan

    Materials (Basel, Switzerland)

    2018  Volume 11, Issue 2

    Abstract: Metal-elastomer interfacial systems, often encountered in stretchable electronics, demonstrate remarkably high interface fracture toughness values. Evidently, a large gap exists between the rather small adhesion energy levels at the microscopic scale (' ... ...

    Abstract Metal-elastomer interfacial systems, often encountered in stretchable electronics, demonstrate remarkably high interface fracture toughness values. Evidently, a large gap exists between the rather small adhesion energy levels at the microscopic scale ('intrinsic adhesion') and the large measured macroscopic work-of-separation. This energy gap is closed here by unravelling the underlying dissipative mechanisms through a systematic numerical/experimental multi-scale approach. This self-containing contribution collects and reviews previously published results and addresses the remaining open questions by providing new and independent results obtained from an alternative experimental set-up. In particular, the experimental studies on Cu-PDMS (Poly(dimethylsiloxane)) samples conclusively reveal the essential role of fibrillation mechanisms at the micro-meter scale during the metal-elastomer delamination process. The micro-scale numerical analyses on single and multiple fibrils show that the dynamic release of the stored elastic energy by multiple fibril fracture, including the interaction with the adjacent deforming bulk PDMS and its highly nonlinear behaviour, provide a mechanistic understanding of the high work-of-separation. An experimentally validated quantitative relation between the macroscopic work-of-separation and peel front height is established from the simulation results. Finally, it is shown that a micro-mechanically motivated shape of the traction-separation law in cohesive zone models is essential to describe the delamination process in fibrillating metal-elastomer systems in a physically meaningful way.
    Language English
    Publishing date 2018-02-02
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma11020231
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  9. Article: Absolute surface coverage measurement using a vibrational overtone.

    Pipino, Andrew C R / Hoefnagels, Johan P M / Watanabe, Noboru

    The Journal of chemical physics

    2004  Volume 120, Issue 6, Page(s) 2879–2888

    Abstract: Determination of absolute surface coverage with sub-monolayer sensitivity is demonstrated using evanescent-wave cavity ring-down spectroscopy (EW-CRDS) and conventional CRDS by employing conservation of the absolute integrated absorption intensity ... ...

    Abstract Determination of absolute surface coverage with sub-monolayer sensitivity is demonstrated using evanescent-wave cavity ring-down spectroscopy (EW-CRDS) and conventional CRDS by employing conservation of the absolute integrated absorption intensity between gas and adsorbed phases. The first C-H stretching overtones of trichloroethylene (TCE), cis-dichloroethylene, and trans-dichloroethylene are probed using the idler of a seeded optical parametric amplifier having a 0.075 cm(-1) line width. Polarized absolute adsorbate spectra are obtained by EW-CRDS using a fused-silica monolithic folded resonator having a finesse of 28 500 at 6050 cm(-1), while absolute absorption cross sections for the gas-phase species are determined by conventional CRDS. A measure of the average transition moment orientation on the surface, which is utilized for the coverage determination, is derived from the polarization anisotropy of the surface spectra. Coverage measurement by EW-CRDS is compared to a mass-spectrometer-based surface-uptake technique, which we also employ for coverage measurements of TCE on thermally grown SiO(2) surfaces. To assess the potential for environmental sensing, we also compare EW-CRDS to optical waveguide techniques developed previously for TCE detection.
    Language English
    Publishing date 2004-02-08
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3113-6
    ISSN 1089-7690 ; 0021-9606
    ISSN (online) 1089-7690
    ISSN 0021-9606
    DOI 10.1063/1.1637338
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