Digital image correlation studies for microscopic strain distribution and damage in dual phase steels

Kang, Jidong; Ososkov, Y.; Embury, J.D.; Wilkinson, David S.

doi:10.1016/j.scriptamat.2007.01.031

Cited by 287 publications

(149 citation statements)

References 3 publications

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“…This increasing fraction of martensite would lead to local strain re-distribution among different phases and inhibit the transformation behaviors, as suggested in previous study (Knijf et al, 2014). Previous research also suggested that the continuous deformation with proper strain and stress partitioning among different phases based on the law of mixture can still keep a hardening potential without transformation and retard the onset of strain localization (Kuang et al, 2009;Knijf et al, 2014;Bouquerel et al, 2006;Kang et al, 2007;Jacques et al, 2007;Lani et al, 2007;Han et al, 2014;Fillafer et al, 2014;Tasan et al, 2014). Of course, this hardening potential should be much weaker than the strong hardening induced by martensite transformation.…”

Section: Discussionmentioning

confidence: 79%

Dynamic shear response and evolution mechanisms of adiabatic shear band in an ultrafine-grained austenite–ferrite duplex steel

Yuan

Bian

Jiang

et al. 2015

Mechanics of Materials

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a b s t r a c tThe dynamic properties of an intercritically annealed 0.2C5Mn steel with ultrafine-grained austenite-ferrite duplex structure were studied under dynamic shear loading. The formation and evolution mechanisms of adiabatic shear band in this steel were then investigated using interrupted experiments at five different shear displacements and the subsequent microstructure observations. The dynamic shear plastic deformation of the 0.2C5Mn steel was observed to have three stages: the strong linear hardening stage followed by the plateau stage, and then the strain softening stage associated with the evolution of adiabatic shear band. High impact shear toughness was found in this 0.2C5Mn steel, which is due to the following two aspects: the strong linear strain hardening by martensite transformation at the first stage, and the suppressing for the formation of shear band by the continuous deformation in different phases through the proper stress and strain partitioning at the plateau stage. The evolution of adiabatic shear band was found to be a two-stage process, namely an initiation stage followed by a thickening stage. The shear band consists of two regions at the thickening stage: a core region and two transition layers. When the adjoining matrix is localized into the transition layers, the grains are refined along with increasing fraction of austenite phase by inverse transformation. However, when the transition layers are transformed into the core region, the fraction of austenite phase is decreased and almost disappeared due to martensite transformation again. These interesting observations in the core region and the transition layers should be attributed to the competitions of the microstructure evolutions associated with the non-uniformly distributed shear deformation and the inhomogeneous adiabatic temperature rise in the different region of shear band. The 0.2C5Mn TRIP steel reported here can be considered as an excellent candidate for energy absorbers in the automotive industry.

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Section: Discussionmentioning

confidence: 79%

Dynamic shear response and evolution mechanisms of adiabatic shear band in an ultrafine-grained austenite–ferrite duplex steel

Yuan

Bian

Jiang

et al. 2015

Mechanics of Materials

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“…The micro-scale deformation of materials has been mostly studied through the observation of microstructural evolution using different techniques including in-situ mechanical testing combined with strain measurements at a microscopic scale [2][3][4][5] with the aim to relate local strain distributions within microstructural constituents to identified deformation mechanisms [6][7][8]. Allais et al [9] developed a technique to measure strain distributions from the distortion of microgrids laid onto the surface of dualphase materials , i.e.…”

Section: Introductionmentioning

confidence: 99%

“…They analysed optical micrographs of the surface of the deforming sample using the DIC technique to obtain strain maps of the analysed region with strain values up to 5 micro-strains. In recent years, the DIC technique has been widely used to quantify the microstructural deformation [2,8]. However, the application of random speckle patterns is practically restricted at this scale, therefore SEM micrographs have been used together with DIC [8,23,24] to measure strain distributions within the microstructure of both dual [2] and single [5,24] phase materials, where the microstructure itself was used to correlate the images.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Strain Analysis of the Large Deformation at the Scale of Microstructure: Comparison between Digital Image Correlation and Microgrid Techniques

2012

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A comparative study has been carried out to assess the accuracy of the Digital Image Correlation (DIC) technique for the quantification of large strains in the microstructure of a Interstitial Free (IF) steel used in automotive applications. A microgrid technique has been used in this study in order to validate independently the strain measurements obtained with DIC. Microgrids with a pitch of 5 microns were printed on the etched microstructure of the IF steel to measure the local in-plane strain distribution during a tensile test carried out in a Scanning Electron Microscope (SEM). The progressive deformation of the microstructure with microgrids has been recorded throughout the test as a sequence of micrographs and subsequently processed using DIC to quantify the distribution of local strain values. Strain maps obtained with the two techniques have been compared in order to assess the accuracy of the DIC measurements obtained using the natural patterns of the revealed microstructure in the SEM micrographs. Although results obtained with the two techniques are qualitatively similar, therefore demonstrating the reliability of DIC applied to microstructures, even after large deformations in excess of 0.7. However, an average error of about 16% was found in the strain values calculated using DIC.

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“…8 A schematic drawing of the miniaturized Marciniak test concept: specimen (yellow); top plate (brown); bottom plate (dark green); punch (light green); long string (red; only one of the three strings is shown); pulleys (blue); and winch (grey) Fig. 9 The components of the miniaturized Marciniak apparatus: the sample and washer (depicted in yellow) are clamped with the clamping ring (1) to the top plate (2), and are deformed by the punch (3) which is mounted on the bottom plate (4). The punch force is supplied by pulling three cables (depicted in red) over 72 pulleys (5) (i.e.…”

Section: Design Of the Miniaturized Marciniak Test Setupmentioning

confidence: 99%

“…Although these techniques have provided clear insight in the behavior of metal microstructures over the past century, thorough understanding of the deformation mechanisms in the complex microstructures of the aforementioned new alloys requires realtime analysis of microstructural deformation mechanisms. Therefore, recent studies employ miniaturized tensile testing equipment inside scanning electron microscopes, e.g., to investigate the influence of tempering [4] or segregation-induced banding [5] in DP steels. These studies clearly demonstrate the benefits of realtime microstructural analysis.…”

Section: Introductionmentioning

confidence: 99%

Multi-Axial Deformation Setup for Microscopic Testing of Sheet Metal to Fracture

et al. 2011

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While the industrial interest in sheet metal with improved specific-properties led to the design of new alloys with complex microstructures, predicting their safe forming limits and understanding their microstructural deformation mechanisms remain as significant challenges largely due to the inadequacy of the existing experimental tools. The investigation of the strain-path dependent failure mechanisms requires miniaturized testing equipment, which can be placed in a scanning electron microscope for in situ experiments. So far, such tests could only be carried out for a single strain path (uniaxial tension). In this work, in order to fill this gap, a miniaturized Marciniak test setup is designed, built and tested. With this setup real-time, multi-axial tests of industrial sheet metal can be carried out to the point of fracture within a

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Digital image correlation studies for microscopic strain distribution and damage in dual phase steels

Cited by 287 publications

References 3 publications

Dynamic shear response and evolution mechanisms of adiabatic shear band in an ultrafine-grained austenite–ferrite duplex steel

Dynamic shear response and evolution mechanisms of adiabatic shear band in an ultrafine-grained austenite–ferrite duplex steel

Quantitative Strain Analysis of the Large Deformation at the Scale of Microstructure: Comparison between Digital Image Correlation and Microgrid Techniques

Multi-Axial Deformation Setup for Microscopic Testing of Sheet Metal to Fracture

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