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Texture comparison between cold rolled and cryogenically rolled pure copper

Lapeire, L. (author), Sidor, J. (author), Martinez Lombardia, E. (author), Verbeken, K. (author), De Graeve, I. (author), Terryn, H.A. (author), Kestens, L.A.I. (author)

Nowadays, there is a considerable scientific interest in bulk ultrafine grained materials, due to their potential for superior mechanical properties. One of the possible formation methods of nano-grained materials is cryogenic rolling. The influence of rolling at cryogenic temperatures has been investigated. Significant differences in the...

conference paper 2015

document

Quantitative correlation between slip patterning and microstructure during tensile elongation in 6xxx series aluminum alloy

Ghodrat, S. (author), Pirgazi, H. (author), Kestens, L.A.I. (author)

To the purpose of evaluating the effect of deformation on the microstructure, aluminum structures were analyzed on tensile strained samples extended to 25% elongation. In the substructure of these deformed samples linear slip patterns were observed, generally confined to the bulk of the grain. In order to study the crystallographic aspect of...

conference paper 2015

document

Grain boundary character distribution derived from three-dimensional microstructure reconstruction

Pirgazi, H. (author), Kestens, L.A.I. (author)

Manual serial sectioning which includes consecutive steps of sample preparation and Electron Back Scattering Diffraction (EBSD) measurement was employed to extract the twodimensional (2D) sections of a pure nickel sample and to reconstruct the three-dimensional (3D) microstructure. A general alignment algorithm based on the minimization of...

conference paper 2015

document

Fully automated orientation relationship calculation and prior austenite reconstruction by random walk clustering

Gomes, E. (author), Kestens, L.A.I. (author)

Two new methods, one for determining the experimentally observed Orientation Relationship (OR) and another for reconstructing prior austenite phase, are proposed. Both methods are based on the angular deviation of the OR at the grain boundaries. The first algorithm identifies the optimum OR using the misorientation distribution of the entire...

conference paper 2015

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Shear banding and its contribution to texture evolution in rotated Goss orientations of BCC structured materials

Nguyen-MInh, T. (author), Sidor, J.J. (author), Petrov, R.H. (author), Kestens, L.A.I. (author)

Due to progressive deformation, the dislocation densities in crystals are accumulated and the resistance of grains to further deformation increases. Homogeneous deformation becomes energetically less favorable, which may result for some orientations in strain localization. In-grain shear banding, a typical kind of localized deformation in metals...

conference paper 2015

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Three-dimensional characterization of grain boundaries in pure nickel by serial sectioning via mechanical polishing

Pirgazi, H. (author), Glowinski, K. (author), Morawiec, A. (author), Kestens, L.A.I. (author)

Five macroscopic boundary parameters can be extracted from three-dimensional orientation maps. Serial sectioning, which includes consecutive steps of material removal, and electron backscatter diffraction (EBSD) measurement were employed to extract a stack of two-dimensional sections of a pure nickel sample. The EBSD patterns were collected from...

journal article 2015

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Effects of Holding Time on Thermomechanical Fatigue Properties of Compacted Graphite Iron Through Tests with Notched Specimens

Ghodrat, S. (author), Riemslag, T.A.C. (author), Kestens, L.A.I. (author), Petrov, R.H. (author), Janssen, M. (author), Sietsma, J. (author)

In cylinder heads of compacted graphite iron (CGI), the heating and cooling cycles can lead to localized cracking due to thermomechanical fatigue (TMF). Traditionally, TMF behavior is studied by thermal cycling of smooth specimens. The resulting number of cycles to failure (Nf) constitutes a single parameter that can be used to predict actual...

journal article 2012

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Orientation dependence of the martensite transformation in a quenched and partitioned steel subjected to uniaxial tension

De Knijf, D. (author), Nguyen-Minh, T. (author), Petrov, R.H. (author), Kestens, L.A.I. (author), Jonas, J.J. (author)

The orientation dependence of the austenite-to-martensite transformation during uniaxial tensile testing was modelled using the phenomenological theory of martensite crystallography and the mechanical driving force. It was validated experimentally by means of electron backscatter diffraction measurements on a pre-defined zone of a quenched and...

journal article 2014

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Advanced Crystal Plasticity Modeling of Multi-Phase Steels: Work-Hardening, Strain Rate Sensitivity and Formability

Galan Lopez, J. (author), Shakerifard, B. (author), Ochoa Avendaño, J.F. (author), Kestens, L.A.I. (author)

This work presents an advanced crystal plasticity model for the simulation of the mechanical behavior of multiphase advanced high-strength steels. The model is based on the Visco-Plastic Self-Consistent (VPSC) model and uses information about the material’s crystallographic texture and grain morphology together with a grain constitutive law. The...

journal article 2021

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Use of local electrochemical methods (SECM, EC-STM) and AFM to differentiate microstructural effects (EBSD) on very pure copper

Martinez Lombardia, Esther (author), Lapeire, Linsey (author), Maurice, Vincent (author), De Graeve, Iris (author), Klein, Lorena (author), Marcus, Philippe (author), Verbeken, Kim (author), Kestens, L.A.I. (author), Gonzalez Garcia, Y. (author), Mol, J.M.C. (author), Terryn, H.A. (author)

When aiming for an increased and more sustainable use of metals a thorough knowledge of the corrosion phenomenon as function of the local metal microstructure is of crucial importance. In this work, we summarize the information presented in our previous publications[1-3] and present an overview of the different local (electrochemical) techniques...

journal article 2017

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Optimization of crystallographic texture for sheet-forming applications using Taylor-based Models

Galan Lopez, J. (author), Kestens, L.A.I. (author)

Plastic deformation of metallic materials is an inherently anisotropic process as a result of the presence of preferential orientations in their crystallographic texture. Crystal plasticity modeling, which allows simulating the response of polycrystal aggregates taking into account their texture and other microstructural parameters, has been...

journal article 2018

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A multivariate grain size and orientation distribution function: Derivation from electron backscatter diffraction data and applications

Galan Lopez, J. (author), Kestens, L.A.I. (author)

Two of the microstructural parameters most influential in the properties of polycrystalline materials are grain size and crystallographic texture. Although both properties have been extensively studied and there are a wide range of analysis tools available, they are generally considered independently, without taking into account the possible...

journal article 2021

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High strain rate torsional response of maraging steel parts produced by laser powder bed fusion techniques: Deformation behavior and constitutive model

Dehgahi, S. (author), Pirgazi, H. (author), Sanjari, M. (author), Seraj, P. (author), Odeshi, A. (author), Kestens, L.A.I. (author), Mohammadi, M. (author)

The deformation performance of maraging steel samples fabricated using the laser powder bed fusion technique was evaluated using the split Hopkinson torsion bar (SHTB) test. Thin-walled tubular maraging steel samples were deformed under dynamic torsional loading at strain rates of 260 s⁻¹ to 720 s⁻¹ using twist angles...

journal article 2022

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Microstructural Evolution in Additively Manufactured Fe-Cr-Ni Maraging Stainless Steel

Shahriari, Ayda (author), Sanjari, Mehdi (author), Pirgazi, H. (author), Fazeli, Fateh (author), Shalchi Amirkhiz, Babak (author), Kestens, L.A.I. (author), Mohammadi, Mohsen (author)

In this work, the effect of heating rate on the phase transformation temperatures was investigated using dilatometry analysis. Continuous heating and isothermal holding above Ac₃ temperature on microstructural evolutions in additively manufactured (AM) parts of Fe-Cr-Ni maraging stainless steel were studied. The microstructural...

journal article 2022

document

Dislocation pileups in small grains

Schouwenaars, R. (author), Kestens, L.A.I. (author)

While the grain size effect (GSE) is universally observed in polycrystalline metals and alloys, extended dislocation pileups (DPUs) at grain boundaries (GBs) are rarely observed. Although this discrepancy was noticed over 50 years ago, DPUs are still widely accepted as the explanation for the GSE, often expressed as the Hall-Petch (HP)...

journal article 2023

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Functional grading of low alloy steel to 316 L by wire arc additive manufacturing – Microstructural and mechanical characterization of bi-metal interface

Galán Argumedo, J.L. (author), Mahmoudiniya, M. (author), Reinton, T.E. (author), Kestens, L.A.I. (author), Hermans, M.J.M. (author), Popovich, V. (author)

This study examines the interface layer between a high-strength low-alloy steel and an overlaying austenitic stainless steel as deposited through wire arc additive manufacturing in a bi-metal block. By utilizing optical and electron microscopy techniques, and accompanied by phenomenological and thermodynamic modeling, the work elucidates on...

journal article 2024

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Evolutions of Microstructure and Crystallographic Texture in an Fe-1.2 wt.% Si Alloy After (A)Symmetric Warm Rolling and Annealing

Nguyen-Minh, Tuan (author), Petrov, R.H. (author), Cicalè, Stefano (author), Kestens, L.A.I. (author)

Rolling and annealing is a crucial technology to produce electrical steel sheets. This technology is not just aimed to control the geometry of steel sheets but more importantly to enhance the magnetic properties of the final products via appropriate microstructure and crystallographic texture. In this study, the evolution of microstructures...

journal article 2024

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Effect of heat treatment on friction and tribolayer formation in copper

Figueroa, Carlos Gabriel (author), Schouwenaars, Rafael (author), Petrov, R.H. (author), Kestens, L.A.I. (author)

This work analyses the effect of annealing conditions on tribolayer formation in copper under dry sliding conditions. Cold rolled material and samples annealed during 15, 30 and 45 min at 600 °C show an increase in grain size, decrease in hardness and increase in toughness and ductility with time. Electron backscattered diffraction maps...

journal article 2022

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The Role of Parent Phase Topology in Double Young–Kurdjumow–Sachs Variant Selection during Phase Transformation in Low-Carbon Steels

Kestens, L.A.I. (author), Nguyen-Minh, Tuan (author), Petrov, R.H. (author)

The present paper investigates the role of parent phase topology on a crystallographic variant selection rule. This rule assumes that product phase nuclei appear at certain grain boundaries in the parent structure, such that a specific crystallographic orientation relationship is observed with both parent grains at either side of the grain...

journal article 2022

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Morphological and crystallographic anisotropy of severely deformed commercially pure aluminium by three-dimensional electron backscatter diffraction

Naghdy, Soroosh (author), Pirgazi, Hadi (author), Verleysen, Patricia (author), Petrov, R.H. (author), Kestens, L.A.I. (author)

International Union of Crystallography. The aim of this paper is to examine the morphological and crystallographic anisotropy that develops during high-pressure torsion (HPT) processing. Commercially pure aluminium was subjected to monotonic HPT deformation at room temperature. The microstructure and texture were studied by large-area electron...

journal article 2017