Publications
70 results found
Avadanii D, Hansen L, Marquardt K, et al., 2023, The Role of Grain Boundaries in Low-Temperature Plasticity of Olivine Revealed by Nanoindentation, JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, Vol: 128, ISSN: 2169-9313
Singh SP, Thom C, Hansen L, et al., 2023, Direct Observation of Grain Boundary Sliding in Forsterite Bicrystals
<jats:p>Olivine is the most abundant mineral in Earth&#8217;s mantle, and its rheology is likely to control upper-mantle convection. While the rheology of olivine is widely studied, little is known about the rheology of olivine grain boundaries and their effect on deformation in the mantle. Forsterite bicrystals, synthesized by direct bonding of highly polished single-crystal plates, were tested in this study to investigate sliding along the single grain boundary at high temperature (1300&#176;C). Prior to deformation, the bicrystals were polished and scratch markers were scribed perpendicular to the grain boundary to track grain-boundary sliding. Bicrystals were deformed in shear loading between two alumina pistons in a uniaxial creep apparatus at 1 atm with applied axial stress ranging from 1 to 30 MPa. The specimen deformation was measured in real time using a high-resolution (~1 &#956;m) linear variable differential transducer. Each test was carried out until attainment of a quasi-steady state deformation rate to determine the creep parameters. Post-deformation microstructural analysis was conducted using a scanning electron microscope (SEM) and electron backscattered diffraction. Our study established that the creep-rate law for bicrystals is different than single and polycrystalline forsterite. Bicrystals are weaker and shows up to 1 order of magnitude higher deformation rates. SEM microstructures reveal the sliding of scratch markers, which is direct evidence of grain-boundary sliding in forsterite. However, the strain geometry is complex, and further experiments are necessary to determine the overall strain distribution in the sample. Here we present the rationale of our research, and we compare our results on grain-boundary sliding in forsterite with the earlier literature.</jats:p>
Cui Y, Xian JW, Zois A, et al., 2023, Nucleation and growth of Ag3Sn in Sn-Ag and Sn-Ag-Cu solder alloys, Acta Materialia, Vol: 249, Pages: 1-15, ISSN: 1359-6454
Large Ag3Sn plates in solder joints can affect the reliability of electronics, however, the factors affecting their nucleation and morphology are not well understood. Here, the faceted solidification of Ag3Sn was studied as a function of melt undercooling, revealing transitions from single crystal {001} plates to cyclic twinned plates and then to highly branched structures created by twin mediated branching. Real-time X-ray imaging proved that Ag3Sn cyclic twins come from a common point, indicating they initiate in the process of nucleation or in the very early stages of growth in the undercooled melt. Soldering to copper substrates significantly catalysed Ag3Sn nucleation. This is shown to be due to constitutional supercooling generated by Ag solute rejection into the liquid ahead of the Cu6Sn5 reaction layer, with additional contributions from geometrical catalysis in the grooves between Cu6Sn5 scallops and heterogeneous nucleation of Ag3Sn on Cu6Sn5. The relative ease of Ag3Sn nucleation on the Cu6Sn5 reaction layer is responsible for the large plates often reported in electronic solder joints.
Satta N, Morales LFG, Criniti G, et al., 2022, Single-Crystal Elasticity of Antigorite at High Pressures and Seismic Detection of Serpentinized Slabs, GEOPHYSICAL RESEARCH LETTERS, Vol: 49, ISSN: 0094-8276
- Author Web Link
- Cite
- Citations: 1
Ferreira F, Thielmann M, Marquardt K, 2022, The role of grain boundaries for the deformation and grain growth of olivine at upper mantle conditions
<jats:p>&lt;p&gt;Crystal defects such as vacancies, dislocations and grain boundaries are central in controlling the rheology of the Earth&amp;#8217;s upper mantle. Their presence influences element diffusion, plastic deformation and grain growth, which are the main microphysical processes controlling mass transfer in the Earth&amp;#8217;s lithosphere and asthenosphere. Although substantial information exists on these processes, there is a general lack of data on how these defects interact at conditions found in the Earth&amp;#8217;s interior. A better understanding of processes occurring at the grain scale is necessary for increased confidence in extrapolating from laboratory length and time scales to those of the Earth. We examined the evolution of olivine grain boundaries during experimental deformation and their impact on deformation in the dislocation-accommodated grain- boundary sliding (disGBS) regime. This may be the main deformation mechanism for olivine in most of Earth&amp;#8217;s upper mantle. Our results suggest that grain boundaries play a major role in moderating deformation in the disGBS regime. We present observational evidence that the rate of deformation is controlled by assimilation of dislocations into grain boundaries. We also demonstrate that the ability for dislocations to transmit across olivine grain boundaries evolves with increasing deformation. Lastly, we show that dynamic recrystallization of olivine creates specific grain boundaries, which are modified as deformation progresses. This might affect electrical conductivity and seismic attenuation in the upper mantle. The effective contribution of grain-boundary processes (such as disGBS) on the rheology of the upper mantle is correlated to the amount of grain boundaries in upper mantle rocks, that is, their grain-size distribution and evolution. The grain-size distribution in the Earth&amp;#8217;s mantle is controlled by the ba
Avadanii D, Hansen L, Darnbrough E, et al., 2022, In-situ mechanical testing and characterization of olivine grain boundaries
<jats:p>&lt;p&gt;The mechanics of olivine deformation play a key role in long-term planetary processes, such as the response of the lithosphere to tectonic loading or the response of the solid Earth to tidal forces, and in short-term processes, such as the evolution of roughness on oceanic fault surfaces or postseismic creep within the upper mantle. Many previous studies have emphasized the importance of grain-size effects in the deformation of olivine. However, most of our understanding of the role of grain boundaries in the deformation of olivine is inferred from comparison of experiments on single crystals to experiments on polycrystalline samples.&lt;/p&gt;&lt;p&gt;To directly observe and quantify the mechanical properties of olivine grain boundaries, we use high-precision mechanical testing of synthetic forsterite bicrystals with well characterised interfaces. We conduct &lt;em&gt;in-situ&lt;/em&gt; micropillar compression tests at high-temperature (700&amp;#176;C) on low-angle (13&amp;#176; tilt about [100] on (015)) and high-angle (60&amp;#176; tilt about [100] on (011)) grain boundaries. In these experiments, the boundary is contained within the micropillar and oriented at 45&amp;#176; to the loading direction to promote shear along the boundary. In these in-situ tests, we observe differences in deformation style between the pillars containing the grain boundary and the pillars in the crystal interior. &lt;em&gt;In-situ&lt;/em&gt; observations and analysis of the mechanical data indicate that pillars containing the grain boundary consistently support elastic loading to higher stresses than pillars without a grain boundary. Moreover, only the pillars without a grain boundary display evidence of sustained plasticity and slip-band formation. Post-deformation advanced microstructural characterization (STEM) confirm
Goebel C, Marquardt K, Baabe D, et al., 2022, Realizing shape and size control for the synthesis of coordination polymer nanoparticles templated by diblock copolymer micelles, NANOSCALE, Vol: 14, Pages: 3131-3147, ISSN: 2040-3364
- Author Web Link
- Cite
- Citations: 4
Beyer C, Myhill R, Marquardt K, et al., 2021, A reversed redox gradient in Earth's mantle transition zone, EARTH AND PLANETARY SCIENCE LETTERS, Vol: 575, ISSN: 0012-821X
- Author Web Link
- Cite
- Citations: 1
Gardes E, Gibouin D, Radiguet B, et al., 2021, Magnesium transport in olivine mantle: new insights from miniaturized study of volume and grain boundary diffusion in Mg<sub>2</sub>SiO<sub>4</sub> bi-crystals, CONTRIBUTIONS TO MINERALOGY AND PETROLOGY, Vol: 176, ISSN: 0010-7999
- Author Web Link
- Cite
- Citations: 1
Ferreira F, Hansen LN, Marquardt K, 2021, The Effect of Grain Boundaries on Plastic Deformation of Olivine, JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, Vol: 126, ISSN: 2169-9313
- Author Web Link
- Cite
- Citations: 7
Gavalda-Diaz O, Lyons J, Wang S, et al., 2021, Basal plane delamination energy measurement in a Ti3SiC2 MAX phase, JOM, Vol: 73, Pages: 1582-1588, ISSN: 1047-4838
The {0001} basal plane delamination dominating the crack-wake bridging in MAX phases at a bulk scale has been investigated by studying the small-scale fracture of a Ti3SiC2. In situ micro-double cantilever beam (DCB) tests in a scanning electron microscope were used to grow a stable crack along the basal plane, measure the fracture energy, and study the crack propagation mechanism at the nanoscale. The results show that the fracture energy (10–50 J/m2) depends on small misorientations angles (e.g., 5°) of the basal plane to the stress field. This induces permanent deformation which can be observed once the DCB has been unloaded. The nanoscale study of the crack shows that the plasticity at the crack tip is small, but a number of pairs of dislocations are forming at each side of the crack. Hence, this study helps to explain the enhanced fracture energy values and possible sources of energy dissipation in basal plane delamination, which is the one of the main toughening mechanisms in the bulk fracture of MAX phases.
Elazar O, Kessel R, Huang J-X, et al., 2021, Silicic microinclusions in a metasomatized eclogite from Roberts Victor mine, South Africa, LITHOS, Vol: 388, ISSN: 0024-4937
- Author Web Link
- Cite
- Citations: 3
Emmanuel M, Gavalda-Diaz O, Sernicola G, et al., 2021, Fracture energy measurement of prismatic plane and Σ2 boundary in cemented carbide, JOM, Vol: 73, Pages: 1589-1596, ISSN: 1047-4838
The grain boundary network of WC in WC-Co is important, as cracks often travel intergranularly. This motivates the present work, where we experimentally measure the fracture energy of Σ2 twist grain boundaries between WC crystals using a double cantilever beam (DCB) opened with a wedge under displacement control in a WC-10wt%Co sample. The fracture energy of this boundary type was compared with cleaving {101 ̅0} prismatic planes in a WC single crystal. Fracture energies of 7.04 ± 0.36 Jm-2 and 3.57 ± 0.28 Jm-2 were measured for {101 ̅0} plane and Σ2 twist boundaries respectively.
Avadanii D, Hansen L, Darnbrough E, et al., 2021, Micromechanical testing of olivine grain boundaries
<jats:p>&lt;p&gt;The mechanics of olivine deformation play a key role in large-scale, long-term planetary processes, such as the response of the lithosphere to tectonic loading or the response of the solid Earth to tidal forces, and in short-term processes, such as the evolution of roughness on oceanic fault surfaces or postseismic creep within the upper mantle. Many previous studies have emphasized the importance of grain-size effects in the deformation of olivine. However, most of our understanding of the role of grain boundaries in deformation of olivine is inferred from comparison of experiments on single crystals to experiments on polycrystalline samples.&lt;/p&gt;&lt;p&gt;To directly observe and quantify the mechanical properties of olivine grain boundaries, we use high-precision mechanical testing of synthetic forsterite bicrystals with well characterised interfaces. We conduct nanoindentation tests at room temperature on low-angle (13&lt;sup&gt;o&lt;/sup&gt; tilt about [100] on (015)) and high-angle (60&lt;sup&gt;o&lt;/sup&gt; tilt about [100] on (011)) grain boundaries. We observe that plasticity is easier to initiate if the grain boundary is within the volume tested. This observation agrees with the interpretation that certain grain-boundary configurations can act as sites for initiating microplasticity.&lt;/p&gt;&lt;p&gt;As part of continuing efforts, we are also conducting in-situ micropillar compression tests at high-temperature (above 600&lt;sup&gt;o&lt;/sup&gt; C) within similar bicrystals. In these experiments, the boundary is contained within the micropillar and oriented at 45&lt;sup&gt;o&lt;/sup&gt; to the loading direction to promote shear along the boundary. In these in-situ tests, our hypothesis is that the low-angle grain boundary dis
Marquardt K, Dobson D, Hunt S, et al., 2021, Grain boundary character information via individual imaging or statistical analyses: complexion transitions and grain boundary segregation
<jats:p>&lt;p&gt;Grain boundaries affect bulk properties of polycrystalline materials, such as electrical conductivity, melting or bulk viscosity. In the past two decades, observations of marked bulk material property changes have been associated with changes in the structure and composition of grain boundaries. This led to the term &amp;#8220;grain boundary complexions&amp;#8221; to mark the phase-like behaviour of grain boundaries while differing from phases in the sense of Gibbs (Cantwell 2014).&lt;/p&gt;&lt;p&gt;Here we introduce the principles of grain boundary structure to property relations and potent methods to study these. The focus is on the combination of structural, chemical and statistical analysis as obtainable using transmission electron microscopy and electron backscatter diffraction. Data from these complementary methods will be discussed on two systems; garnet and olivine polycrystals.&lt;/p&gt;&lt;p&gt;Past elasticity measurements showed that the Youngs modulus of garnet polycrystals changes as a function of sintering pressure (Hunt et al. 2016). Here we used high resolution transmission electron microscopy to study the structure of grain boundaries from polycrystals synthesized at low (4-8 GPa) and high (8-15) GPa sintering pressure. The HRTEM data were acquired using an image-corrected JEOL ARM 300 to achieve the highest resolution at low electron doses using a OneView camera. Our data indicate a grain boundary structural change occurs from &amp;#8220;low-pressure&amp;#8221; to &amp;#8220;high pressure&amp;#8221; grain boundaries, where the grain boundary facets change from &gt;100 nm &amp;#8211; 20 nm to 3-7 nm length scale, respectively. We conclude that sintering pressure affects grain-boundary strength and we will evaluate how this may influence anelastic energy loss of seismic waves through el
Polednia J, Dohmen R, Marquardt K, 2020, Grain boundary diffusion and its relation to segregation of multiple elements in yttrium aluminum garnet, EUROPEAN JOURNAL OF MINERALOGY, Vol: 32, Pages: 675-696, ISSN: 0935-1221
- Author Web Link
- Cite
- Citations: 5
Anzolini C, Marquardt K, Stagno V, et al., 2020, Evidence for complex iron oxides in the deep mantle from FeNi(Cu) inclusions in superdeep diamond, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 117, Pages: 21088-21094, ISSN: 0027-8424
- Author Web Link
- Cite
- Citations: 8
Diaz OG, Marquardt K, Harris S, et al., 2020, Degradation mechanisms of SiC/BN/SiC after low temperature humidity exposure, Journal of the European Ceramic Society, Vol: 40, Pages: 3863-3874, ISSN: 0955-2219
The environmental degradation of SiC/BN/SiC CMCs under low temperature water exposure is still an unexplored field. This work shows how the effect of low temperature humid environments can be detrimental for turbostratic BN interphases, leading to a drop in mechanical properties. Furthermore, initial low-temperature humid environments can induce a faster degradation during subsequent thermal exposure. In order to understand how low temperature water exposure affects the CMC and how these changes affect the material response to subsequent exposures, intermediate temperature (800 °C) exposures have been studied before and after the low temperature humidity tests. The main challenge of this work consists of understanding how different constituents of the CMC structure (e.g. fibres and interphases) are degrading and consequently affecting the overall bulk mechanical performance and failure modes of the material. For this, linking the change in morphology and chemistry of the interphases with the micromechanical properties each constituent has been crucial.
Salama H, Kundin J, Shchyglo O, et al., 2020, Role of inclination dependence of grain boundary energy on the microstructure evolution during grain growth, ACTA MATERIALIA, Vol: 188, Pages: 641-651, ISSN: 1359-6454
- Author Web Link
- Cite
- Citations: 34
Beyer C, Dohmen R, Rogalla D, et al., 2019, Lead diffusion in CaTiO<sub>3</sub>: A combined study using Rutherford backscattering and TOF-SIMS for depth profiling to reveal the role of lattice strain in diffusion processes, AMERICAN MINERALOGIST, Vol: 104, Pages: 557-568, ISSN: 0003-004X
- Author Web Link
- Cite
- Citations: 5
Bollinger C, Marquardt K, Ferreira F, 2019, Intragranular plasticity vs. grain boundary sliding (GBS) in forsterite: Microstructural evidence at high pressures (3.5-5.0 GPa), AMERICAN MINERALOGIST, Vol: 104, Pages: 220-231, ISSN: 0003-004X
Schulze K, Marquardt H, Kawazoe T, et al., 2018, Seismically invisible water in Earth’s transition zone?, Earth and Planetary Science Letters, Vol: 498, ISSN: 0012-821X
© 2018 Elsevier B.V. Ringwoodite, the dominant mineral at depths between 520 km and 660 km, can store up to 2–3 wt.% of water in its crystal structure, making the Earth’s transition zone a plausible water reservoir that plays a central role in Earth’s deep water cycle. Experiments show that hydration of ringwoodite significantly reduces elastic wave velocities at room pressure, but the effect of pressure remains poorly constrained. Here, a novel experimental setup enables a direct quantification of the effect of hydration on ringwoodite single-crystal elasticity and density at pressures of the Earth’s transition zone and high temperatures. Our data show that the hydration-induced reduction of seismic velocities almost vanishes at conditions of the transition zone. Seismic data thus agree with a wide range of water contents in the transition zone.
Fei H, Koizumi S, Sakamoto N, et al., 2018, Pressure, temperature, water content, and oxygen fugacity dependence of the Mg grain-boundary diffusion coefficient in forsterite, AMERICAN MINERALOGIST, Vol: 103, Pages: 1354-1361, ISSN: 0003-004X
- Author Web Link
- Cite
- Citations: 7
Fei H, Koizumi S, Sakamoto N, et al., 2018, Mg lattice diffusion in iron-free olivine and implications to conductivity anomaly in the oceanic asthenosphere, Earth and Planetary Science Letters, Vol: 484, Pages: 204-212, ISSN: 0012-821X
© 2017 Elsevier B.V. Mg lattice diffusion coefficients in iron-free olivine aggregates were measured as a function of pressure from 1 to 13 GPa, temperature from 1100 to 1300 K, and bulk water content from less than 1 up to 350 wt. ppm using multi-anvil apparatus and secondary ion mass spectrometer in depth profiling mode. The water contents in the samples were analyzed by Fourier transmission infrared spectrometer. The results show that Mg lattice diffusion coefficient increase with increasing temperature and water content, and decrease with pressure. The activation energy, water content exponent, and activation volume are 250 ± 30 kJ/mol, 1.2 ± 0.2, and 4.3 ± 0.3 cm 3 /mol, respectively. Since Mg lattice diffusion controls the ionic conduction in olivine based on the Nernst–Einstein relation, the ionic conductivity in the upper mantle appears as a maximum at the top of oceanic asthenosphere due to the negative correction for pressure and positive correction for water content, which well explains the high conductivity anomaly observed at ∼70–120 km depth beneath young oceanic plates.
Marquardt K, Faul UH, 2018, The structure and composition of olivine grain boundaries: 40 years of studies, status and current developments, Physics and Chemistry of Minerals, Vol: 45, Pages: 139-172, ISSN: 0342-1791
Kutzschbach M, Guttmann P, Marquardt K, et al., 2018, A transmission x-ray microscopy and NEXAFS approach for studying corroded silicate glasses at the nanometre scale, PHYSICS AND CHEMISTRY OF GLASSES-EUROPEAN JOURNAL OF GLASS SCIENCE AND TECHNOLOGY PART B, Vol: 59, Pages: 11-26, ISSN: 1753-3562
- Author Web Link
- Cite
- Citations: 2
Marquardt K, 2018, Weathering of Bi-bearing tennantite, Chemical Geology, ISSN: 0009-2541
Marquardt K, De Graef M, Singh S, et al., 2017, Quantitative electron backscatter diffraction (EBSD) data analyses using the dictionary indexing (DI) approach: Overcoming indexing difficulties on geological materials, American Mineralogist, Vol: 102, Pages: 1843-1855, ISSN: 0003-004X
Cernok A, Marquardt K, Caracas R, et al., 2017, Compressional pathways of alpha-cristobalite, structure of cristobalite X-I, and towards the understanding of seifertite formation, Nature Communications, Vol: 8, Pages: 1-10, ISSN: 2041-1723
In various shocked meteorites, low-pressure silica polymorph α-cristobalite is commonly found in close spatial relation with the densest known SiO2 polymorph seifertite, which is stable above ∼80 GPa. We demonstrate that under hydrostatic pressure α-cristobalite remains untransformed up to at least 15 GPa. In quasi-hydrostatic experiments, above 11 GPa cristobalite X-I forms—a monoclinic polymorph built out of silicon octahedra; the phase is not quenchable and back-transforms to α-cristobalite on decompression. There are no other known silica polymorphs, which transform to an octahedra-based structure at such low pressures upon compression at room temperature. Further compression in non-hydrostatic conditions of cristobalite X-I eventually leads to the formation of quenchable seifertite-like phase. Our results demonstrate that the presence of α-cristobalite in shocked meteorites or rocks does not exclude that materials experienced high pressure, nor is the presence of seifertite necessarily indicative of extremely high peak shock pressures.
Laumonier M, Farla R, Frost DJ, et al., 2017, Experimental determination of melt interconnectivity and electrical conductivity in the upper mantle, EARTH AND PLANETARY SCIENCE LETTERS, Vol: 463, Pages: 286-297, ISSN: 0012-821X
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.