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Journal articleHaug M, Bouville F, Ruiz-Agudo C, et al., 2020,
Cold densification and sintering of nanovaterite by pressing with water
, JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, Vol: 40, Pages: 893-900, ISSN: 0955-2219- Author Web Link
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- Citations: 15
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Journal articleElizarova I, Vandeperre L, Saiz Gutierrez E, 2020,
Conformable green bodies: plastic forming of robocasted advanced ceramics
, Journal of the European Ceramic Society, Vol: 40, Pages: 552-557, ISSN: 0955-2219Robocasting, or the additive manufacturing of ceramics by continuous extrusion of a ceramic paste, has limited capabilities when printing complex unsupported structures such as overhangs or free standing thin artefacts. In this paper we address this limitation using a new type of paste, which allows for shaping of the green bodies after printing. To illustrate the flexibility of the paste, it was used to produce both alumina and silicon carbide parts. The paste consists of a solution of phenolic resin in methyl ethyl ketone and ceramic powders. Fabricated parts can be cut, bent, folded and draped over various objects. Once dry and fully solid, the parts become rigid and can be processed further by slow pyrolysis and sintering. Sintered samples exhibit flexural strength comparable to both conventionally produced and robocasted ceramics and shaping of the green bodies after printing does not affect the mechanical strength of the sintered parts.
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Journal articlePeng J, Huang C, Cao C, et al., 2020,
Inverse Nacre-like Epoxy-Graphene Layered Nanocomposites with Integration of High Toughness and Self-Monitoring
, MATTER, Vol: 2, Pages: 220-232, ISSN: 2590-2393 -
Journal articlePelissari PIBGB, Pandolfelli VC, Carnelli D, et al., 2020,
Refractory interphase and its role on the mechanical properties of boron containing nacre-like ceramic
, JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, Vol: 40, Pages: 165-172, ISSN: 0955-2219- Author Web Link
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- Citations: 9
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Journal articleWang S, Kalácska S, Maeder X, et al., 2019,
The effect of δ-hydride on the micromechanical deformation of Zircaloy-4 studied by in situ high angular resolution electron backscatter diffraction
, Scripta Materialia, Vol: 173, Pages: 101-105, ISSN: 1359-6462Zircaloy-4(Zr-1.5%Sn-0.2%Fe-0.1%Cr wt%)is usedas nuclear fuel cladding materials and hydride embrittlementis amajor failure mechanism. To explore the effect of δ-hydrideon plastic deformation and performance of Zircaloy-4, in situhigh angular resolution electron backscatter diffraction(HR-EBSD)was used to quantify stress andgeometrically necessarydislocation(GND)density during bending tests of hydride-free and hydride-containingsingle crystalZircaloy-4 microcantilevers. Results suggest that while the stress applied was accommodated by plastic slip in the hydride-free cantilever,the hydride-containing cantilever showedprecipitation-induced GND pile-up at hydride-matrix interfacepre-deformation, andconsiderable locally-increasing GNDdensity under tensile stressupon plastic deformation.
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Journal articleGiuliani F, Ciurea C, Bhakhri V, et al., 2019,
Deformation behaviour of TiN and Ti–Al–N coatings at 295 to 573 K
, Thin Solid Films, Vol: 688, ISSN: 0040-6090Temperature-dependent nanoindentation testing was employed to investigate the deformation behaviour of magnetron sputtered (100) TiN and Ti1-xAlxN (x = 0.34, 0.52, 0.62) coatings in the temperature range from 295 to 573 K. The maximum temperature is sufficiently below the deposition temperature of 773 K to guarantee for stable microstructure and stress state during testing. The TiN coating displayed the same hardness as bulk single crystal (SC) TiNbulk. The addition of aluminium to TiN (to form single-phase face centred cubic structured Ti1-xAlxN coatings) increased the room temperature hardness due to increased bond strength, lattice strain and higher activation energy for the dislocation slip. For coatings with a low aluminium content, Ti0.66Al0.34N, the decrease in hardness with temperature was similar to the TiN coating and SC-TiNbulk. In contrast, the hardness of coatings with moderate, Ti0.48Al0.52N, and high, Ti0.38Al0.62N, aluminium contents varied little up to 573 K. Thus, the Ti1-xAlxN matrix is mechanically more stable at elevated temperatures than its TiN relative, by providing a lower decrease in lattice resistance to the dislocation flow with increasing temperature. The findings suggest that the addition of Al to TiN (to form Ti1-xAlxN solid solutions) not only improves the hardness but also leads to stable hardness with temperature, and emphasizes the importance of bonding states and chemical fluctuations, next to structure and morphology of the coatings that develop with changing the chemistry.
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Journal articleFeilden E, Glymond D, Saiz E, et al., 2019,
High temperature strength of an ultra high temperature ceramic produced by additive manufacturing
, Ceramics International, Vol: 45, Pages: 18210-18214, ISSN: 0272-8842In this study hafnium diboride was fabricated using the additive manufacturing technique robocasting. Parts have been successfully produced with complex shapes and internal structures not possible via conventional manufacturing techniques. Following pressureless sintering, the monolithic parts reach densities of 94–97% theoretical. These parts exhibit bending strength of 364 ± 31 MPa at room temperature, and maintain strengths of 196 ± 5 MPa up to 1950 °C, which is comparable to UHTC parts produced by traditional means. These are the highest temperature mechanical tests that a 3D printed part has ever undergone. The successful printing of the high density HfB2 demonstrates the versatile range materials that can be produced via robocasting using Pluronic pastes.
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Journal articleDel Carro L, Zinn AA, Ruch P, et al., 2019,
Oxide-Free Copper Pastes for the Attachment of Large-Area Power Devices
, Journal of Electronic Materials, Vol: 48, Pages: 6823-6834, ISSN: 0361-5235 -
Journal articleWat A, Ferraro C, Deng X, et al., 2019,
Bioinspired nacre-like alumina with a metallic nickel compliant phase fabricated by spark-plasma sintering
, Small, Vol: 15, ISSN: 1613-6810Many natural materials present an ideal "recipe" for the development of future damage-tolerant lightweight structural materials. One notable example is the brick-and-mortar structure of nacre, found in mollusk shells, which produces high-toughness, bioinspired ceramics using polymeric mortars as a compliant phase. Theoretical modeling has predicted that use of metallic mortars could lead to even higher damage-tolerance in these materials, although it is difficult to melt-infiltrate metals into ceramic scaffolds as they cannot readily wet ceramics. To avoid this problem, an alternative ("bottom-up") approach to synthesize "nacre-like" ceramics containing a small fraction of nickel mortar is developed. These materials are fabricated using nickel-coated alumina platelets that are aligned using slip-casting and rapidly sintered using spark-plasma sintering. Dewetting of the nickel mortar during sintering is prevented by using NiO-coated as well as Ni-coated platelets. As a result, a "nacre-like" alumina ceramic displaying a resistance-curve toughness up to ≈16 MPa m½ with a flexural strength of ≈300 MPa is produced.
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Journal articleMagrini T, Bouville F, Lauria A, et al., 2019,
Transparent and tough bulk composites inspired by nacre
, NATURE COMMUNICATIONS, Vol: 10, ISSN: 2041-1723- Author Web Link
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- Citations: 87
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Journal articleLe Ferrand H, Bouville F, 2018,
Processing of dense bioinspired ceramics with deliberate microstructure
, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, ISSN: 0002-7820 -
Journal articleD'Elia E, Ahmed HS, Feilden E, et al., 2019,
Electrically-responsive graphene-based shape-memory composites
, Applied Materials Today, Vol: 15, Pages: 185-191, ISSN: 2352-9407Shape memory materials can open new design opportunities in fields as diverse as healthcare, transportation or energy generation. In this respect, shape memory polymers (SMPs) have attracted much attention due to their advantages over metals in terms of weight and reliability. However, they are still marred by slow reaction times and poor mechanical performance. In this work we show how, by integrating a graphene network in a SMP matrix, it is possible to create composites with very low carbon contents (below 1 wt%) able to change shapes in short times (10 s of seconds) in response to low electric voltages (<10 V). This is possible because the conductive network is highly interconnected at the microscopic scale, acting as a very efficient Joule heater. The composites exhibit excellent shape fixity (>0.95 ± 0.03) and shape recovery ratios (>0.98 ± 0.03). Due to the 2D nature of graphene, this network directs crack propagation during fracture resulting in materials that retain bending strengths close to 100 MPa and exhibit significant extrinsic toughening (with toughness that reach values up to 3 times the initiation value). Furthermore, changes in conductivity can be used to follow the formation and growth of damage in the material before catastrophic failure, allowing the use of this material as a damage sensor. These results provide practical guidelines for the design of reliable shape memory composites for structural and sensing applications.
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Journal articleBoughton O, Ma S, Cai X, et al., 2019,
Computed tomography porosity and spherical indentation for determining cortical bone millimetre-scale mechanical properties
, Scientific Reports, Vol: 9, ISSN: 2045-2322The cortex of the femoral neck is a key structural element of the human body, yet there is not a reliable metric for predicting the mechanical properties of the bone in this critical region. This study explored the use of a range of non-destructive metrics to measure femoral neck cortical bone stiffness at the millimetre length scale. A range of testing methods and imaging techniques were assessed for their ability to measure or predict the mechanical properties of cortical bone samples obtained from the femoral neck of hip replacement patients. Techniques that can potentially be applied in vivo to measure bone stiffness, including computed tomography (CT), bulk wave ultrasound (BWUS) and indentation, were compared against in vitro techniques, including compression testing, density measurements and resonant ultrasound spectroscopy. Porosity, as measured by micro-CT, correlated with femoral neck cortical bone’s elastic modulus and ultimate compressive strength at the millimetre length scale. Large-tip spherical indentation also correlated with bone mechanical properties at this length scale but to a lesser extent. As the elastic mechanical properties of cortical bone correlated with porosity, we would recommend further development of technologies that can safely measure cortical porosity in vivo.Introduction
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Journal articleWang S, Giuliani F, Britton TB, 2019,
Microstructure and formation mechanisms of δ-hydrides in variable grain size Zircaloy-4 studied by electron backscatter diffraction
, Acta Materialia, Vol: 169, Pages: 76-87, ISSN: 1359-6454Microstructure and crystallography of δ phase hydrides in as-received fine grain and ‘blocky alpha’ large grain Zircaloy-4 (average grain size ∼11 μm and >200 μm, respectively) were examined using electron backscatter diffraction (EBSD). Results suggest that the matrix-hydride orientation relationship is {0001} α ||{111} δ ;<112¯0> α ||<110> δ for all the cases studied. The habit plane of intragranular hydrides and some intergranular hydrides has been found to be {101¯7} of the surrounding matrix. The morphology of intergranular hydrides can vary depending upon the angle between the grain boundary and the hydride habit plane. The misfit strain between α-Zr and δ-hydride is accommodated mainly by high density of dislocations and twin structures in the hydrides, and a mechanism of twin formation in the hydrides has been proposed. The growth of hydrides across grain boundaries is achieved through an auto-catalytic manner similar to the growth pattern of intragranular hydrides. Easy collective shear along <11¯00> makes it possible for hydride nucleation at any grain boundaries, while the process seems to favour grain boundaries with low (<40°) and high (>80°) c-axis misorientation angles. Moreover, the angle between the grain boundary and the adjacent basal planes does not influence the propensity for hydride nucleation.
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Journal articleLe Ferrand H, Bouville F, Studart AR, 2019,
Design of textured multi-layered structures via magnetically assisted slip casting.
, Soft MatterMulti-layered composites in nature often show functional properties that are determined by the specific orientation of inorganic building blocks within each layer. The shell of bivalve molluscs and the exoskeleton of crustaceans constitute prominent examples. An effective approach to artificially produce textured microstructures inspired by such complex composites is magnetically assisted slip casting (MASC). MASC is a colloidal process in which anisotropic particles are magnetically oriented at arbitrarily defined angles and collected at the surface of a porous mould to grow the material in an additive manner. Whereas a number of proof-of-concept studies have established the potential of the technique, the full design space available for MASC-fabricated structures, and the limits of the approach, have so far not been explored systematically. To fill this gap, we have studied both theoretically and experimentally the various torques that act on the particles at the different stages of the assembly process. We define the boundary conditions of the MASC process for magnetically responsive alumina platelets suspended in a low-viscosity aqueous suspension, considering the composition of the colloidal suspension and the dynamics of the particle alignment process under a rotating magnetic field. These findings lead to design guidelines for the fabrication of bio-inspired composites with customized multi-scale structures for a broad range of applications.
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Journal articleWang S, Giuliani F, Britton T, 2019,
Variable temperature micropillar compression to reveal <a> basal slip properties of Zircaloy-4
, Scripta Materialia, Vol: 162, Pages: 451-455, ISSN: 1359-6462Zircaloy-4 is widely used as nuclear fuel cladding materials, where it is important to understand the mechanical properties between room temperature and reactor operating temperatures (around 623 K). To aid in this understanding, we have performed compression tests on micropillars aligned to activate <a> basal slip across this temperature range. Engineering analysis of the results indicates that the plastic yield follows a thermally activated constitutive law. We also observe the nature of the slip bands formed on the side surface of our pillars and see characteristic ‘bulging’ that tends to localise as temperature increases.
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Journal articleGrossman M, Pivovarov D, Bouville F, et al., 2019,
Hierarchical Toughening of Nacre-Like Composites
, ADVANCED FUNCTIONAL MATERIALS, Vol: 29, ISSN: 1616-301X -
Journal articleJun T-S, Maeder X, Bhowmik A, et al., 2019,
The role of β-titanium ligaments in the deformation of dual phase titanium alloys
, Materials Science and Engineering: A, Vol: 746, Pages: 394-405, ISSN: 0921-5093Multiphase titanium alloys are critical materials in high value engineeringcomponents, for instance in aero engines. Microstructural complexity isexploited through interface engineering during mechanical processing to realisesignificant improvements in fatigue and fracture resistance and strength. Inthis work, we explore the role of select interfaces using in-situmicromechanical testing with concurrent observations from high angularresolution electron backscatter diffraction (HR-EBSD). Our results aresupported with post mortem transmission electron microscopy (TEM). Usingmicro-pillar compression, we performed in-depth analysis of the role of select{\beta}-titanium (body centred cubic) ligaments which separate neighbouring{\alpha}-titanium (hexagonal close packed) regions and inhibit the dislocationmotion and impact strength during mechanical deformation. These results shedlight on the strengthening mechanisms and those that can lead to strainlocalisation during fatigue and failure.
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Journal articleAlison L, Menasce S, Bouville F, et al., 2019,
3D printing of sacrificial templates into hierarchical porous materials
, SCIENTIFIC REPORTS, Vol: 9, ISSN: 2045-2322- Author Web Link
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- Citations: 61
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Journal articleCaballero SSR, Saiz E, Montembault A, et al., 2019,
3-D printing of chitosan-calcium phosphate inks: rheology, interactions and characterization
, Journal of Materials Science: Materials in Medicine, Vol: 30, ISSN: 0957-4530Bone substitute fabrication is of interest to meet the worldwide incidence of bone disorders. Physical chitosan hydrogels with intertwined apatite particles were chosen to meet the bio-physical and mechanical properties required by a potential bone substitute. A set up for 3-D printing by robocasting was found adequate to fabricate scaffolds. Inks consisted of suspensions of calcium phosphate particles in chitosan acidic aqueous solution. The inks are shear-thinning and consist of a suspension of dispersed platelet aggregates of dicalcium phosphate dihydrate in a continuous chitosan phase. The rheological properties of the inks were studied, including their shear-thinning characteristics and yield stress. Scaffolds were printed in basic water/ethanol baths to induce transformation of chitosan-calcium phosphates suspension into physical hydrogel of chitosan mineralized with apatite. Scaffolds consisted of a chitosan polymeric matrix intertwined with poorly crystalline apatite particles. Results indicate that ink rheological properties could be tuned by controlling ink composition: in particular, more printable inks are obtained with higher chitosan concentration (0.19 mol·L−1).
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Journal articleMinas C, Rechberger F, Tervoort E, et al., 2018,
Freezing of Gelled Suspensions: a Facile Route toward Mesoporous TiO2 Particles for High-Capacity Lithium-Ion Electrodes
, ACS APPLIED NANO MATERIALS, Vol: 1, Pages: 6622-6629, ISSN: 2574-0970 -
Journal articleGrossman M, Bouville F, Masania K, et al., 2018,
Quantifying the role of mineral bridges on the fracture resistance of nacre-like composites
, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 115, Pages: 12698-12703, ISSN: 0027-8424 -
Journal articleWang X, Peng J, Zhang Y, et al., 2018,
Ultratough Bioinspired Graphene Fiber via Sequential Toughening of Hydrogen and Ionic Bonding
, ACS NANO, Vol: 12, Pages: 12638-12645, ISSN: 1936-0851 -
Journal articleZhang Y, Peng J, Li M, et al., 2018,
Bioinspired supertough graphene fiber through sequential interfacial interactions.
, ACS Nano, Vol: 12, Pages: 8901-8908, ISSN: 1936-0851Natural nacre exhibits extraordinary functional and structural diversity, combining high strength and toughness. The mechanical properties of nacre are attributed to (i) a highly arranged hierarchical layered structure of inorganic minerals (95 vol %) containing a small amount only of organic materials (5 vol %), (ii) abundant synergistic interfacial interactions, and (iii) formation under ambient temperature. Herein, inspired by these three design principles originating from natural nacre, the supertough bioinspired graphene-based nanocomposite fibers (BGNFs) are prepared under room temperature via sequential interfacial interactions of ionic bonding and π-π interactions. The resultant synergistic effect leads to a super toughness of 18.7 MJ m-3 as well as a high tensile strength of 740.1 MPa. In addition, the electrical conductivity of these supertough BGNFs is as high as 384.3 S cm-1. They can retain almost 80% of this conductivity even after 1000 cycles of loading-unloading testing, which makes these BGNFs promising candidates for application in flexible and stable electrical devices, such as strain sensors and actuators.
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Journal articleBoughton OR, Ma S, Zhao S, et al., 2018,
Measuring bone stiffness using spherical indentation
, PLoS ONE, Vol: 13, ISSN: 1932-6203ObjectivesBone material properties are a major determinant of bone health in older age, both in terms of fracture risk and implant fixation, in orthopaedics and dentistry. Bone is an anisotropic and hierarchical material so its measured material properties depend upon the scale of metric used. The scale used should reflect the clinical problem, whether it is fracture risk, a whole bone problem, or implant stability, at the millimetre-scale. Indentation, an engineering technique involving pressing a hard-tipped material into another material with a known force, may be able to assess bone stiffness at the millimetre-scale (the apparent elastic modulus). We aimed to investigate whether spherical-tip indentation could reliably measure the apparent elastic modulus of human cortical bone.Materials and methodsCortical bone samples were retrieved from the femoral necks of nineteen patients undergoing total hip replacement surgery (10 females, 9 males, mean age: 69 years). The samples underwent indentation using a 1.5 mm diameter, ruby, spherical indenter tip, with sixty indentations per patient sample, across six locations on the bone surfaces, with ten repeated indentations at each of the six locations. The samples then underwent mechanical compression testing. The repeatability of indentation measurements of elastic modulus was assessed using the co-efficient of repeatability and the correlation between the bone elastic modulus measured by indentation and compression testing was analysed by least-squares regression.ResultsIn total, 1140 indentations in total were performed. Indentation was found to be repeatable for indentations performed at the same locations on the bone samples with a mean co-efficient of repeatability of 0.4 GigaPascals (GPa), confidence interval (C.I): 0.33–0.42 GPa. There was variation in the indentation modulus results between different locations on the bone samples (mean co-efficient of repeatability: 3.1 GPa, C.I: 2.2–3.90 GPa). No cle
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Journal articleGasparrini C, Chater RJ, Horlait D, et al., 2018,
Zirconium carbide oxidation: kinetics and oxygen diffusion through the intermediate layer
, Journal of the American Ceramic Society, Vol: 101, Pages: 2638-2652, ISSN: 0002-7820Oxidation of hot‐pressed ZrC was investigated in air in the 1073‐1373 K range. The kinetics were linear at 1073 K, whereas at higher temperature samples initially followed linear kinetics before undergoing rapid oxidation leading to a Maltese cross shape of the oxide. The linear kinetics at 1073 K was governed by inward oxygen diffusion through an intermediate layer of constant thickness between ZrC and ZrO2 which was comprised of amorphous carbon and ZrO2 nanocrystals. Diffusion of oxygen through the intermediate layer was measured to be 9 × 10−10 cm2 s−1 using 18O as a tracer in a double oxidation experiment in 16O/18O. Oxidation at 1073 and 1173 K produced samples made of m‐ZrO2 and either t‐ or c‐ZrO2 with an adherent intermediate layer made of amorphous carbon and ZrO2, whereas oxidation at 1273 and 1373 K produced samples with a voluminous oxide made of m‐ZrO2 showing a gap between ZrC and the oxide. A substoichiometric zirconia layer was found at the gap at 1273 K and no carbon uptake was detected in this layer when compared with the top oxide layer. The loss of the intermediate layer and the slowdown of the linear rate constant (g m−2 s−1) at 1273 K compared to 1173 K was correlated with the preferential oxidation of carbon at the intermediate layer which would leave as CO and/or CO2 leaving a gap between ZrC and substoichiometric zirconia.
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Journal articlePelissari PIBGB, Bouville F, Pandolfelli VC, et al., 2018,
Nacre-like ceramic refractories for high temperature applications
, Journal of the European Ceramic Society, Vol: 38, Pages: 2186-2193, ISSN: 0955-2219High-temperature ceramics, so-called refractories, are widely used for the manufacturing of metals, for energy generation and aerospace applications. Refractories are usually strong and stiff but fragile due to the lack of plastic deformation and other intrinsic toughening mechanisms. This inherent brittleness limits their use in applications where catastrophic failure is not tolerated. The present work reports the design and fabrication of refractories with a bio inspired nacre-like microstructure comprising aligned alumina platelets, separated by an aluminium borate interphase, obtained through transient liquid phase sintering. The bioinspired composites exhibit high strength, 672 MPa, toughness, 7.4 MPa m1/2, and stable crack propagation at high temperatures, above 600 °C, due to the aluminium borate interlayer. This makes nacre-like ceramic refractories sintered with a transient liquid phase good candidate for high temperature applications, competing favourably with ceramic matrix composites and following a simpler and cheaper processing route.
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Journal articleSaiz E, Boccaccini AR, Chevalier J, et al., 2018,
Editorial on Bioceramics for Bone Repair
, JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, Vol: 38, Pages: 821-822, ISSN: 0955-2219 -
Journal articleCal E, Qi J, Preedy O, et al., 2018,
Functionalised magnetic nanoparticles for uranium adsorption with ultra-high capacity and selectivity
, Journal of Materials Chemistry A, Vol: 6, Pages: 3063-3073, ISSN: 2050-7496The removal of radioactive contaminants from the environment for safe and efficient waste disposal is a critical challenge, requiring the development of novel selective and high-capacity sequestering materials. In this paper the design of superparamagnetic iron oxide nanoparticles (SPIONs) as highly efficient magnetic-sorbent structures for uranium (U(VI)) separation is described. The nanosorbent was developed by surface functionalisation of single crystalline magnetite (Fe3O4) nanoparticles with a phosphate-based complex coating. This new design allowed for the development of a magnetically separable ultra-effective sorbent, with a measured U(VI) sorption capacity of ∼2333 mg U per g Fe (1690 mg U per g Fe3O4 NP), significantly higher than everything previously reported. Based on TEM analysis, it is proposed that these properties are the result of a multi-layer ligand structure, which enables a high degree of U-incorporation compared to conventional surface-ligand systems. Moreover, the phosphate-NP construct ((PO)x-Fe3O4) shows exceptionally high specificity for the sequestration of U(VI) in solution at pH 7. Adsorption tests in the presence of competing ions, such as Sr(II), Ca(II) and Mg(II), showed high selectivity of the nanoparticles for U(VI) and extremely rapid kinetics of contaminant removal from solution, with the total amount of uranyl ions being removed after only 60 seconds of contact with the NPs. The results presented in this paper highlight the potential of such a phosphate-functionalised magnetic nanosorbent as a highly effective material for the remediation of U(VI) from contaminated water and industrial scenarios.
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Journal articleBhowmik A, Britton TB, Lee J, et al., 2018,
Deformation behaviour of [001] oriented MgO using combined in-situ nano-indentation and micro-Laue diffraction
, Acta Materialia, Vol: 145, Pages: 516-531, ISSN: 1359-6454We report a coupled in-situ micro-Laue diffraction and nano-indentation experiment, with spatial and time resolution, to investigate the deformation mechanisms in [001]-oriented single crystal MgO. Crystal plasticity finite element modelling was applied to aid interpretation of the experimental observations of plasticity. The Laue spots showed both rotation and streaking upon indentation that is typically indicative of both elastic lattice rotation and plastic strain gradients respectively in the material. Multiple facets of streaking of the Laue peaks suggested plastic slip occurring on almost all the {101}-type slip planes oriented 45° to the sample surface with no indication of slip on the 90° {110} planes. Crystal plasticity modelling also supported these experimental observations. Owing to asymmetric slip beneath the indenter, as predicted by modelling results and observed through Laue analysis, sub-grains were found to nucleate with distinct misorientation. With cyclic loading, the mechanical hysteresis behaviour in MgO is revealed through the changing profiles of the Laue reflections, driven by reversal of plastic strain by the stored elastic energy. Crystal plasticity simulations have also shown explicitly that in subsequent loading cycles after first, the secondary slip system unloads completely elastically while some plastic strain of the primary slip reverses. Tracking the Laue peak movement, a higher degree of lattice rotation was seen to occur in the material under the indent, which gradually decreased moving laterally away. With the progress of deformation, the full field elastic strain and rotation gradients were also constructed which showed opposite lattice rotations on either sides of the indent.
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