| 1. |
|
|
| 2. |
- Ai, Chao, et al.
(författare)
-
Current Development on Origami/Kirigami‐Inspired Structure of Creased Patterns toward Robotics
- 2021
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 23:10, s. 2100473-2100473
-
Tidskriftsartikel (refereegranskat)abstract
- Origami/kirigami, the ancient art of paper folding and cutting techniques, has provided considerable inspiration for structural design routes in the engineering and medical fields over the last few decades. The practicability of the methods and concepts of origami/kirigami has been demonstrated in several emerging classes of technologies, e.g., stretchable electronics, deformable devices, self-assembly fabrication, etc. More and more related products are produced pursuing a folding form for better storage, deformation capacity, and multifunction realization. Herein, the innovative creased patterns of origami/kirigami designs are distinguished and discussed, and the four most widely used creased pattern types are introduced, which may potentially provide origami/kirigami related inspiration and additional solutions toward many research fields.
|
|
| 3. |
- Altamimi, S., et al.
(författare)
-
On Stiffness, Strength, Anisotropy, and Buckling of 30 Strut-Based Lattices with Cubic Crystal Structures
- 2022
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 24:7
-
Tidskriftsartikel (refereegranskat)abstract
- Architected cellular structures are increasingly receiving attention in numerous applications due to advances in additive manufacturing and their promising multi-functional properties. Herein, 30 architected strut-based lattices of cubic crystal symmetry are developed and their stiffness and strength are investigated computationally and experimentally. Finite element simulations are conducted to compute the effective stiffness, yield strength, and buckling strength under uniaxial, shear, and hydrostatic loadings. Also, elastic anisotropy is assessed and bifurcation analysis is performed to estimate the threshold relative density for each lattice. Selected lattices of various relative densities are 3D printed from a polymeric material using selective laser sintering (SLS). The numerical results show that the modes of deformation whether stretching-dominated, bending-dominated, or mixed differ for the various loading conditions. It is observed that by combining different lattice structures in a hybrid approach, a decrease in the anisotropic behavior is obtained, and an overall enhancement of the mechanical properties is achieved. The numerical results show rather good agreement with the experimental findings. The current study can be crucial for using the investigated lattices for enhancing the multi-functional properties of structural systems.
|
|
| 4. |
- Alvi, Sajid, et al.
(författare)
-
Enhanced mechanical, thermal and electrical properties of high‐entropy HfMoNbTaTiVWZr thin film metallic glass and its nitrides
- 2022
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons. - 1438-1656 .- 1527-2648. ; 24:9
-
Tidskriftsartikel (refereegranskat)abstract
- The inception of high-entropy alloy promises to push the boundaries for new alloy design with unprecedented properties. This work reports entropy stabilisation of an octonary refractory, HfMoNbTaTiVWZr, high-entropy thin film metallic glass, and derived nitride films. The thin film metallic glass exhibited exceptional ductility of ≈60% strain without fracture and compression strength of 3 GPa in micro-compression, due to the presence of high density and strength of bonds. The thin film metallic glass shows thermal stability up to 750 °C and resistance to Ar-ion irradiation. Nitriding during film deposition of HfMoNbTaTiVWZr thin film of strong nitride forming refractory elements results in deposition of nanocrystalline nitride films with compressive strength, hardness, and thermal stability of up to 10 GPa, 18.7 GPa, and 950 °C, respectively. The high amount of lattice distortion in the nitride films leads to its insulating behaviour with electrical conductivity as low as 200 S cm−1 in the as-deposited film. The design and exceptional properties of the thin film metallic glass and derived nitride films may open up new avenues of development of bulk metallic glasses and the application of refractory-based high entropy thin films in structural and functional applications.
|
|
| 5. |
- Andersson Ersman, Peter, et al.
(författare)
-
Flexible Active Matrix Addressed Displays Manufactured by Screen Printing
- 2020
-
Ingår i: Advanced Engineering Materials. - : Wiley-VCH Verlag. - 1438-1656 .- 1527-2648. ; 23
-
Tidskriftsartikel (refereegranskat)abstract
- A flexible, electrochromic, active matrix addressed display (AMAD) is demonstrated. The monolithically integrated AMAD, which contains a 3 × 3 array of organic electrochromic smart pixels (OESPs), is manufactured on a plastic substrate solely using screen printing. Each OESP is based on the combination of one organic electrochromic display (OECD) and one organic electrochemical transistor (OECT), where both devices are screen printed into multilayered vertical architectures. The conduction state of the OECT enables control of the color state of its corresponding OECD, thereby circumventing cross-talk effects in the resulting AMAD device. The manufacturing approach also involves electrical wires, which connect each OECD with its corresponding OECT and also serve as the addressing lines of the resulting AMAD device, that are formed by screen printing of an ink based on either silver or nanocopper.
|
|
| 6. |
- Andersson Ersman, Peter, et al.
(författare)
-
Integration of Screen Printed Piezoelectric Sensors for Force Impact Sensing in Smart Multifunctional Glass Applications
- 2022
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons, Ltd. - 1438-1656 .- 1527-2648. ; 24:11
-
Tidskriftsartikel (refereegranskat)abstract
- Screen printed piezoelectric polyvinylidene fluoride?trifluoro ethylene (PVDF?TrFE)-based sensors laminated between glass panes in the temperature range 80?110?°C are presented. No degradation of the piezoelectric signals is observed for the sensors laminated at 110?°C, despite approaching the Curie temperature of the piezoelectric material. The piezoelectric sensors, here monitoring force impact in smart glass applications, are characterized by using a calibrated impact hammer system and standardized impact situations. Stand-alone piezoelectric sensors and piezoelectric sensors integrated on poly(methyl methacrylate) are also evaluated. The piezoelectric constants obtained from the measurements of the nonintegrated piezoelectric sensors are in good agreement with the literature. The piezoelectric sensor response is measured by using either physical electrical contacts between the piezoelectric sensors and the readout electronics, or wirelessly via both noncontact capacitive coupling and Bluetooth low-energy radio link. The developed sensor concept is finally demonstrated in smart window prototypes, in which integrated piezoelectric sensors are used to detect break-in attempts. Additionally, each prototype includes an electrochromic film to control the light transmittance of the window, a screen printed electrochromic display for status indications and wireless communication with an external server, and a holistic approach of hybrid printed electronic systems targeting smart multifunctional glass applications.
|
|
| 7. |
- Andersson Ersman, Peter, et al.
(författare)
-
Reflective and Complementary Transmissive All-Printed Electrochromic Displays Based on Prussian Blue
- 2023
-
Ingår i: Advanced Engineering Materials. - : John Wiley and Sons Inc. - 1438-1656 .- 1527-2648. ; 25:6
-
Tidskriftsartikel (refereegranskat)abstract
- By combining the electrochromic (EC) properties of Prussian blue (PB) and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), complementary EC displays manufactured by slot-die coating and screen printing on flexible plastic substrates are reported. Various display designs have been realized, resulting in displays operating in either transmissive or reflective mode. For the transmission mode displays, the color contrast is enhanced by the complementary switching of the two EC electrodes PB and PEDOT:PSS. Both electrodes are either exhibiting a concurrent colorless or blue appearance. For the displays operating in reflection mode, a white opaque electrolyte is used in conjunction with the EC properties of PB, resulting in a display device switching between a fully white state and a blue-colored state. The developments of the different device architectures, that either operate in reflection or transmission mode, demonstrate a scalable manufacturing approach of all-printed EC displays that may be used in a large variety of Internet of Things applications. © 2022 The Authors.
|
|
| 8. |
- Asadpoordarvish, Amir, et al.
(författare)
-
A Flexible Encapsulation Structure for Ambient-Air Operation of Light-Emitting Electrochemical Cells
- 2016
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 18:1, s. 105-110
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The emerging field of organic electronics is heralded because it promises low-cost and flexible devices, and it was recently demonstrated that a light-emitting electrochemical cell (LEC) can be fabricated with cost-efficient methods under ambient air. However, the LEC turns sensitive to oxygen and water during light-emission, and it is therefore timely to identify flexible encapsulation structures. Here, we demonstrate that a multilayer film, featuring a water and oxygen barrier property of ≈1 × 10–3 g/m2/day and ≈1 × 10–3 cm3/m2/bar/day respectively, is fit for this task. By sandwiching an LEC between such multilayer barriers, as attached by a UV-curable epoxy, we realize flexible LECs with performance on par with identical glass-encapsulated devices, and which remain functional after one year storage under air.
|
|
| 9. |
- Belgardt, Christian, et al.
(författare)
-
Self-Assembly of Ordered Colloidal Nanoparticle Films in Few-Micron Wide Laser-Desorbed Lines of Octadecylsiloxane Monolayers on Silicon Oxide Surfaces
- 2014
-
Ingår i: Advanced Engineering Materials. - : Wiley-VCH Verlag. - 1438-1656 .- 1527-2648. ; 16:9, s. 1090-1097
-
Tidskriftsartikel (refereegranskat)abstract
- We report about a maskless technique to deposit colloidal polystyrene particles in patterned stripes with a line width as narrow as 1.5m. Our approach is based on the digital patterning of a hydrophobic octadecylsiloxane self-assembled monolayer (SAM) on a silicon oxide surface by laser-assisted decomposition and desorption of its organic parts. For hydrophilic stripes of the micropatterned SAM area down to widths of approximately 1.5m, we observed ordered, mainly monolayered stripes of colloidal polystyrene nanoparticles using a modified vertical deposition technique, dipping the silicon substrate into a colloidal suspension at an angle of around 45 degrees with respect to the surface normal of the liquid. The mechanism of this so-called slope self-assembly [Wu et al., Langmuir2013, 29, 14017] and its limitations with respect to stacking can be explained in the framework of a meniscus moving along the steps of alternating surface energy with the decreasing width of the hydrophilic stripes during the deposition process [Fustin et al., Langmuir2004, 20, 9114].
|
|
| 10. |
- Berts, Ida, et al.
(författare)
-
Polymeric Smart Coating Strategy for Titanium Implants
- 2014
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 16:11, s. 1340-1350
-
Tidskriftsartikel (refereegranskat)abstract
- Hyaluronan based hydrogel coatings can mimic extracellular matrix components and incorporate growth factors that can be released during a progressive degradation while new tissue regenerates. This paper describes a structural characterization of a hydrogel coating made of modified hyaluronan polymers and how these coatings interact with bone morphogenetic protein-2 (BMP-2). Quartz crystal microbalance and neutron reflectivity measurements were used for in-situ, real-time measurements of the adsorption properties of polymers and proteins on smooth titanium oxide surfaces that mimic implant products in orthopedics. The adsorption of BMP-2 on a bare titanium oxide surface is compared to that on titanium oxide coated with different chemically modified hyaluronan, the most important being hyaluronan with bisphosphonate groups (HA-BP). The subsequent release of the BMP-2 from these hydrogel coatings could be triggered by calcium ions. The amount of adsorbed protein on the surfaces as well as the amount of released protein both depend on the type of hyaluronan coating. We conclude that HA-BP coated titanium oxide surfaces provide an excellent material for growth factor delivery in-vivo.
|
|
| 11. |
- Blankenburg, Malte, et al.
(författare)
-
Revealing Precipitate Development During Hot Rolling and Cooling of a Ti–Nb Micro-Alloyed High Strength Low-Alloy Steel through X-Ray Scattering
- 2023
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 25:9
-
Tidskriftsartikel (refereegranskat)abstract
- High-energy synchrotron X-ray small-angle scattering (SAXS) is used to study the precipitate development during hot rolling and cooling of a commercial Ti–Nb micro-alloyed, high-strength, low-alloy (HSLA) steel. To study precipitation during hot rolling conditions, Gleeble and dilatometer trials are made. Samples are then studied at room temperature using SAXS in conjunction with transmission electron microscopy (TEM). TEM is used to determine the morphology and composition of the precipitates, whilst both TEM and SAXS are used to study the particle sizes. One major advantage with high-energy SAXS is the ability to make measurements after a minimum of sample preparation and in transmission geometry, as opposed to just at prepared surfaces, plus the possibility to determine volume fractions of the precipitates. The measurements show that after deformation at high temperature, particle coarsening occurs and the volume fraction of precipitates increases after holding for 20 s at 900 °C which confirms strain-induced precipitation at finishing rolling conditions. The measurements show that holding at 600 or 650 °C for one hour gives a larger volume fraction of nanosized particles. Coiling simulations with slow cooling from 600 to 470 °C show coarsening of particles and an increase in the volume fraction of the smaller particles compared to holding at a constant temperature.
|
|
| 12. |
- Chastellain, M., et al.
(författare)
-
Superparamagnetic silica-iron oxide nanocomposites for application in hyperthermia
- 2004
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 6:4, s. 235-241
-
Tidskriftsartikel (refereegranskat)abstract
- Superparamagnetic iron oxide particles embedded in silica are studied for application in hyperthermia. The temperature increase is studied when submitting the samples to a weak alternating magnetic field. The influence of the iron oxide size distribution, saturation magnetization, out of phase susceptibility and anisotropy constant is discussed. A theoretical calculation of power loss is carried out and agrees with experimental data.
|
|
| 13. |
|
|
| 14. |
- Dadbakhsh, Sasan, et al.
(författare)
-
In situ formation of particle reinforced Al matrix composite by selective laser melting of Al/Fe 2O 3 powder mixture
- 2012
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1527-2648 .- 1438-1656. ; 14:1-2, s. 45-48
-
Tidskriftsartikel (refereegranskat)abstract
- This work presents a novel in situ reaction approach to produce Al matrix composites from a powder mixture of Al/5a wt% Fe 2O 3 by using selective laser melting (SLM). It is found that the SLM process not only is able to produce three-dimensional parts, but also is capable of activating an in situ reaction in the powder mixture, producing particles mainly from alumina (Al 2O 3) and iron combinations (such as Fe 2+Al 2O 4) in Al matrix. These particles (as reinforcements) can be distributed uniformly with a good particle/matrix interface under controlled conditions.
|
|
| 15. |
- Dadbakhsh, Sasan, et al.
(författare)
-
Selective Laser Melting to Manufacture "In Situ" Metal Matrix Composites: A Review
- 2019
-
Ingår i: Advanced Engineering Materials. - : WILEY-V C H VERLAG GMBH. - 1438-1656 .- 1527-2648. ; 21:3
-
Forskningsöversikt (refereegranskat)abstract
- After a brief introduction on selective laser melting (SLM) and ex situ manufacture of metal matrix composites (MMCs), this paper reviews the capacities and benefits of SLM to activate and control various in situ reactions during fabrication of 3D parts. It introduces several systems (such as Al/Fe2O3, AlSi10Mg/SiC, Al/ZnO, Ti/C, Ti/SiC, Ti/Si3N4, Ti/Mo2C, Fe/SiC, etc.) used to manufacture Al-based, Ti-based, and steel-based in situ MMCs. Then, it illustrates the novel microstructural characteristics of these SLM-made in situ MMCs for different cases, as they may appear from nano-particles to nano-whiskers and dendritic reinforcements homogeneously distributed in a metal matrix. It also focuses on SLM associated in situ mechanisms, explaining how an in situ reaction propagates based on decomposition, diffusion, and reformation and how the growth mechanisms turn into different morphologies such as rounded particles, whiskers, or polygonal block shapes. The influence of various SLM parameters (such as energy density, laser power/speed, powder layer thickness, and the size of initial powder particles) and the SLM in situ challenges are also discussed.
|
|
| 16. |
- Epishin, Alexander, et al.
(författare)
-
Synchrotron Sub-μ X-ray Tomography of Kirkendall Porosity in a Diffusion Couple of Nickel-Base Superalloy and Nickel after Annealing at 1250 °C
- 2021
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1527-2648 .- 1438-1656. ; 23:4
-
Tidskriftsartikel (refereegranskat)abstract
- Kirkendall porosity that forms during interdiffusion in a diffusion couple of nickel-base superalloy CMSX-10 with pure nickel is investigated. The diffusion experiments are conducted at a temperature of 1250 °C, where the strengthening γ′-phase is partially dissolved. The porosity is studied by X-ray sub-μ tomography with a spatial resolution of about 0.353 μm3 at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. It is found that depending on the distance from the interface the Kirkendall pores take different shapes: octahedral, rounded pyramidal, drop shaped, dendritic, pear shaped, and joint shapes. Such a variety of pore morphologies indicates a complex multistage process of porosity nucleation and growth under vacancy supersaturation of different degrees. The experimental findings are interpreted on the basis of the results of diffusion modeling. It is shown that the kinetics of porosity growth is essentially influenced by the dissolution of the γ′-phase.
|
|
| 17. |
- Faisal, Nadimul Haque, et al.
(författare)
-
Thermal Spray Coatings for Electromagnetic Wave Absorption and Interference Shielding : A Review and Future Challenges
- 2022
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons. - 1438-1656 .- 1527-2648.
-
Tidskriftsartikel (refereegranskat)abstract
- This review aims to consolidate scattered literature on thermally sprayed coatings with nonionizing electromagnetic (EM) wave absorption and shielding over specific wavelengths potentially useful in diverse applications (e.g., microwave to millimeter wave, solar selective, photocatalytic, interference shielding, thermal barrier-heat/emissivity). Materials EM properties such as electric permittivity, magnetic permeability, electrical conductivity, and dielectric loss are critical due to which a material can respond to absorbed, reflected, transmitted, or may excite surface electromagnetic waves at frequencies typical of electromagnetic radiations. Thermal spraying is a standard industrial practice used for depositing coatings where the sprayed layer is formed by successive impact of fully or partially molten droplets/particles of a material exposed to high or moderate temperatures and velocities. However, as an emerging novel application of an existing thermal spray techniques, some special considerations are warranted for targeted development involving relevant characterization. Key potential research areas of development relating to material selection and coating fabrication strategies and their impact on existing practices in the field are identified. The study shows a research gap in the feedstock materials design and doping, and their complex selection covered by thermally sprayed coatings that can be critical to advancing applications exploiting their electromagnetic properties.
|
|
| 18. |
- Fan, Xuge, et al.
(författare)
-
Deformation Behavior and Mechanical Properties of Suspended Double-Layer Graphene Ribbons Induced by Large Atomic Force Microscopy Indentation Forces
- 2022
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 24:3, s. 2100826-
-
Tidskriftsartikel (refereegranskat)abstract
- Atomic force microscopy (AFM) indentation experiments are commonly used to study the mechanical properties of graphene, such as Young's modulus and strength. However, applied AFM indentation forces on suspended graphene beams or ribbons are typically limited to several tens of nanonewtons due to the extreme thinness of graphene and their sensitivity to damage caused by the AFM tip indentation. Herein, graphene ribbons with a Si mass attached to their center position are employed, allowing us to introduce an unprecedented, wide range of AFM indentation forces (0–6800 nN) to graphene ribbons before the graphene ribbons are ruptured. It is found that the Young's modulus of double-layer graphene ribbons decreases as the applied AFM indentation force is larger than ≈3000 nN, which indicates that the stiffness of double-layer graphene ribbons remains constant before exposing them to AFM indentation forces larger than ≈3000 nN.
|
|
| 19. |
|
|
| 20. |
- Gren, Daniel, 1994, et al.
(författare)
-
Fatigue Crack Characteristics in Gradient Predeformed Pearlitic Steel under Multiaxial Loading
- 2024
-
Ingår i: Advanced Engineering Materials. - 1527-2648 .- 1438-1656. ; In Press
-
Tidskriftsartikel (refereegranskat)abstract
- Rolling contact fatigue of railway rails not only severely deforms the surface material near the rail head, but also induces an anisotropy in the mechanical behavior due to work hardening and alignment of the microstructure along the shear direction. Cracks typically initiate in this region and propagate along the aligned microstructure. The fatigue behavior of rails is evaluated under uniaxial loading in the undeformed material state. However, this is not representative of the contact loading condition and material performance after years of service. Herein, the nonproportional multiaxial fatigue of as-received and biaxially predeformed pearlitic rail steel R260 is investigated. Four material states are investigated, corresponding to the microstructure found at different depths from the severely deformed surface material at the rail head. A starting notch is machined by electrical discharge machining to control crack initiation and allow for comparable surface crack propagation measurements. The crack path is found to be strongly influenced by the degree of predeformation while the early surface crack propagation rate is found to be similar for all material states.
|
|
| 21. |
|
|
| 22. |
- Hua, Jing, 1989-, et al.
(författare)
-
Controllable Friction of Green Ionic Liquids via Environmental Humidity
- 2020
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons. - 1438-1656 .- 1527-2648. ; 22:5
-
Tidskriftsartikel (refereegranskat)abstract
- Intelligent control of friction is an attractive but challenging topic. In this work, it is investigated if it would be possible to adjust friction in a lubricated contact by controlling environmental humidity. By exploiting the ability to adjust the environmental humidity by various saturated salt solutions, friction behavior of contacts lubricated with Choline l‐Proline ([Cho][Pro]) is modulated in a wide range of relative humidity (RH). The friction increases when the environmental humidity is increased and decreases when water is partially evaporated to a lower RH. It is thus possible to control friction by environmental humidity. The addition of water in ionic liquids (ILs) causes a decrease in viscosity, but as the tests are calculated to be performed in boundary lubrication the viscosity change is not the main factor for the change in friction. The friction sensitivity of RH can be explained by the effect of adhesion on the water uptake from humid air by [Cho][Pro]. Furthermore, the reversible changes of H‐bond types determined by the water content could be another explanation to the altered friction.
|
|
| 23. |
- Jadhav, Suraj Dinkar, et al.
(författare)
-
Modification of Electrical and Mechanical Properties of Selective Laser-Melted CuCr0.3 Alloy Using Carbon Nanoparticles
- 2019
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons. - 1438-1656 .- 1527-2648. ; n/a:n/a
-
Tidskriftsartikel (refereegranskat)abstract
- Herein, the influence of carbon nanoparticle addition on the selective laser melting (SLM) behavior and the resultant properties of gas-atomized CuCr0.3 powder are investigated. The carbon addition neither affects the powder flowability, nor its packing density, but it significantly enhances the optical absorption for infrared radiation. Despite the improved optical absorption of the powder bed after carbon addition, a comparable SLM behavior is observed for both virgin and carbon-mixed CuCr0.3 powders. Furthermore, the addition of carbon nanoparticles facilitates in situ deoxidation of copper and chromium oxides present in the CuCr0.3 powder. Accordingly, a larger fraction of chromium is obtained in its metallic form in the as-built carbon-mixed CuCr0.3 part. The presence of metallic chromium allows tailoring of the mechanical and electrical properties by postheat treatments (HTs). The best combination of mechanical (tensile strength of 298?±?19?MPa, yield strength of 208?±?18?MPa, ductility of 21?±?4%) and electrical (87?±?1% international annealed copper standards [% IACS]) properties is realized for the carbon-mixed CuCr0.3 alloy after a direct age hardening HT. The improvement in mechanical properties is attributed to the precipitation of nanometer-sized, coherent, and metallic chromium precipitates in the copper matrix.
|
|
| 24. |
- Kanhed, Satish, et al.
(författare)
-
Microporous Hydroxyapatite Ceramic Composites as Tissue Engineering Scaffolds : An Experimental and Computational Study
- 2018
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 20:7
-
Tidskriftsartikel (refereegranskat)abstract
- Bone‐tissue engineering mandates the development of multi‐functional bioactive porous hydroxyapatite (HAp) scaffolds. Herein, microwave sintered HAp/ZnO and HAp/Ag composite scaffolds with ≈5–19% porosity are developed using 0–30 vol% graphite as a porogen. The mechanical properties of the porous scaffold are analyzed in detail, revealing that even being more porous, the reinforcement of ZnO (9% porosity, hardness of 2.8 GPa, and toughness of 3.5 MPa.m1/2) has shown to have better hardness and fracture toughness when compared to Ag (5% porosity, hardness of 1.6 GPa, and toughness of 2.6 MPa.m1/2). The flexural strength obtained experimentally are complemented with a finite‐element technique that adopts microstructural features in visualizing the effect of porosity on stress distribution. The antibacterial efficacy and cytocompatibility of these composites are validated by increased metabolic activity and conspicuous cell‐matrix interactions. The anticipation of the results reveal that HAp/ZnO (9% porosity) and HAp/Ag (5% porosity) composites can be used as a potential multi‐functional bone implant scaffolds.
|
|
| 25. |
|
|
| 26. |
|
|
| 27. |
- Laurila, Elina, 1981, et al.
(författare)
-
Enhanced Synthesis of Metal-Organic Frameworks on the Surface of Electrospun Cellulose Nanofibers
- 2015
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1527-2648 .- 1438-1656. ; 17:9, s. 1282-1286
-
Tidskriftsartikel (refereegranskat)abstract
- This study reports the in situ crystal growth of HKUST-1 on electrospun cellulose nanofibers. Two different methods for introducing carboxyl groups on the nanofiber surface were used; HKUST-1 was then synthesized on the cellulose nanofiber surface using a layer-by-layer approach. The distribution of HKUST-1 on the nanofiber surface was highly dependent on the type of anionic pretreatment. The loading of HKUST-1 on the nanofiber surface could be controlled by the layer-by-layer synthesis and the BET surface area could be increased by a factor of 44 to 440 m2 g-1.
|
|
| 28. |
- Le, Fu, et al.
(författare)
-
Max Phases as Nanolaminate Materials : Chemical Composition, Microstructure, Synthesis, Properties and Applications
- 2021
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons. - 1438-1656 .- 1527-2648. ; 23:4
-
Forskningsöversikt (refereegranskat)abstract
- In recent years, MAX phases, a family of nanolaminate materials, have garnered tremendous research interest worldwide, due to the fact that they possess an excellent combination of both metallic and ceramic characteristics. The number of publications on MAX phases has experienced an almost exponential increase in the past decade. The main objective herein is to develop a comprehensive understanding of MAX phases, meanwhile presenting the recent progress and development of MAX phases. The Review starts with introducing the chemical composition of MAX phases, followed by reviewing the microstructure, which includes both the well-known 211, 312, and 413 structures and the newly discovered out-of-plane ordered and in-plane ordered structures. A wide range of synthesis methods are reviewed, such as traditional hot pressing, pressure-less sintering, and recently reported substitutional solid-liquid reaction method. The chemical and physical properties of MAX phases are summarized. The potential fields of applications for MAX phases are surveyed, such as high-temperature materials, nuclear materials, precursors for MXene, etc. In addition, an outlook for future research on MXX phases is also presented.
|
|
| 29. |
- Lin, Zeyu, et al.
(författare)
-
A Systematic Approach to Optimize Parameters in Manufacturing Complex Lattice Structures of NiTi Using Electron Beam Powder Bed Fusion Process
- 2024
-
Ingår i: Advanced Engineering Materials. - : Wiley-VCH Verlagsgesellschaft. - 1438-1656 .- 1527-2648. ; 26:10
-
Tidskriftsartikel (refereegranskat)abstract
- Herein, the quality and accuracy to manufacture delicate parts from NiTi powder using electron beam powder bed fusion (EB-PBF) technology is investigated. Therefore, benchmarks with thin cylinders and thin walls are designed and fabricated using two distinct scan strategies of EB-PBF manufacturing (i.e., continuous melting and spot melting) with different process parameter sets. After these optimizations, four different lattice structures (i.e., octahedron, cell gyroid, sheet gyroid, and channel) are manufactured and characterized. It is shown both continuous melting and spot melting modes are able to manufacture lattices with relative densities over 97%. And as-built lattice structures exhibit an excellent pseudoelasticity up to 8% depending on the design of the structure, e.g., the channel structure shows more deformation recoverability than the cell gyroid. This is attributed to the integrity of geometry as well as compressive mode of the mechanical loading. Of course, the compressive strength and ultimate compressive strength also increase with the increasing volume fraction. Moreover, the spot melting can be used as an engineering tool to customize a delicate beam-shaped structure with a superior pseudoelasticity.This study explores the precision of electron beam powder bed fusion (EB-PBF) for NiTi parts using continuous and spot melting scan strategies for the density and mechanical properties.image (c) 2024 WILEY-VCH GmbH
|
|
| 30. |
- Lin, Zeyu, 1991-, et al.
(författare)
-
Influence of Electron Beam Powder Bed Fusion Process Parameters on Transformation Temperatures and Pseudoelasticity of Shape Memory Nickel Titanium
- 2023
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons. - 1438-1656 .- 1527-2648. ; 25:12
-
Tidskriftsartikel (refereegranskat)abstract
- Electron beam powder bed fusion (PBF-EB) is used to manufacture dense nickel titanium parts using various parameter sets, including the beam current, scan speed, and postcooling condition. The density of manufactured NiTi parts is investigated in relation to the linear energy input. The results imply that the part density increases with increasing linear energy density to over 98% of the bulk density. With a constant energy input, a combination of low power and low scan speed leads to denser parts. This is attributed to lower electrostatic repulsive forces from lower number density of the impacting electrons. After manufacturing, the densest parts with distinct parameter sets are categorized into three groups: 1) high power with high scan speed and vacuum slow cooling, 2) low power with low scan speed and vacuum slow cooling, and 3) low power with low scan speed and medium cooling rate in helium gas. Among these, a faster cooling rate suppresses phase transformation temperatures, while vacuum cooling combinations do not affect the phase transformation temperatures significantly. Herein, all the printed parts exhibit almost 8% pseudoelasticity regardless of the process parameters, while the parts cooled in helium have a higher energy dissipation efficiency (1 − η), which implies faster damping of oscillations. © 2023 The Authors. Advanced Engineering Materials published by Wiley-VCH GmbH.
|
|
| 31. |
- Liu, Yanan, et al.
(författare)
-
Fabrication and Characterization of Highly Porous FeAl‐Based Intermetallics by Thermal Explosion Reaction
- 2019
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons. - 1438-1656 .- 1527-2648. ; 21:4
-
Tidskriftsartikel (refereegranskat)abstract
- Porous FeAl-based intermetallics with different nominal compositions ranging from Fe–40 at% Al to Fe–60 at% Al are prepared by a novel process of thermal explosion (TE) mode. The results show that the Al content significantly affects the combustion behavior of the specimens, the ignition temperature of the Fe–Al intermetallics varies from 641 to 633 °C and the combustion temperature from 978 to 1179 °C. The porous materials exhibit uniform pore structures with porosities and average pore sizes of 52–61% and 20–25 µm, respectively. The TE reaction is the dominant pore formation mechanism regardless of the alloy composition. However, differences in the porosity and average pore size are observed depending on the Al content. The compressive strength of porous Fe–Al intermetallics is in the range of 23–34 MPa, duly applied as filters. Additionally, a surface alumina layer is formed at the early stage and both of the oxidation process and the sulfidation process follows the familiar parabolic rate law in the given atmosphere, exhibiting excellent resistance to oxidation and sulfidation. These results suggest that the porous Fe–Al intermetallics are promising materials for applications in harsh environments with a high-temperature sulfide-bearing atmosphere, such as in the coal chemical industry.
|
|
| 32. |
|
|
| 33. |
- Malladi, Bala, 1993, et al.
(författare)
-
Additive Manufacturing of Interstitial Nitrogen-Strengthened CoCrNi Medium Entropy Alloy
- 2024
-
Ingår i: Advanced Engineering Materials. - 1527-2648 .- 1438-1656. ; In Press
-
Tidskriftsartikel (refereegranskat)abstract
- Equiatomic CoCrNi medium entropy alloy (MEA) is known for its excellent mechanical properties, oxidation resistance, and hydrogen embrittlement resistance. Interstitial elements like carbon and nitrogen further enhance these properties. However, there is limited research on interstitial solid solution-strengthened alloys produced via powder bed fusion-laser beam (PBF-LB). This study investigates the role of nitrogen as an interstitial alloying element in CoCrNi MEA using PBF-LB. Two alloy variants, one without nitrogen and one prealloyed with nitrogen, are analyzed through thermodynamic calculations and experimental validations. A minor nitrogen loss occurs in as-printed samples compared to prealloyed powders, but the remaining nitrogen stays as an interstitial solid solution without forming detrimental secondary phases. This leads to improved mechanical properties, with yield and ultimate tensile strengths increasing from about 690 and 900 MPa in nitrogen-free samples to over 750 and 1000 MPa in nitrogen-containing samples while maintaining the high ductility of the nitrogen-free counterpart in the as-printed materials. Additionally, the nitrogen-containing CoCrNi-N MEA exhibits ≈35HV higher hardness than the nitrogen-free variant in both as-printed and heat-treated states. These findings highlight the benefits of nitrogen addition in enhancing the mechanical properties of CoCrNi MEA produced by PBF-LB.
|
|
| 34. |
- Mapelli, Valeria, 1978, et al.
(författare)
-
Viability Study of the Use of Cast Iron Open Cell Foam as Microbial Fuel Cell Electrodes
- 2013
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1527-2648 .- 1438-1656. ; 15:3, s. 112-117
-
Tidskriftsartikel (refereegranskat)abstract
- Nowadays, the development of new green technologies has been promoted worldwide both by public andprivate institutions. In this context the research on microbial fuel cells (MFC) represents a promisingalternative to carbon based energy sources. Unfortunately, this technology has been always affected by too lowcurrent density output for allowing an intensive application in the industrial and civil field. The study dealswith this limitation and focuses on the implementation of metallic sponges, specifically cast iron based, aselectrodes, aiming at increasing the exposed surface and thus the current density at the MFC anode. Cast ironwas selected because of its low toxicity for the microorganisms, however its high melting point carries severalproblems for the manufacture process. Parallel to this, the realization of electrodes using foamed metals impliesfurther issues related to the generation of correct pore size distribution and adequate bacterial activity. Forinstance, the metal foams are expected to be open-cell type, so that there can be an efficientmass transport alsoto the inner regions of the electrode. In order to control these parameters the metal sponges are produced byinfiltration of cast iron on ceramic beds. Combining previous data with themeasurements of power generationefficiency the authors conclude the study attempting to design MFCs with metal foamed electrodes.
|
|
| 35. |
- Martin, Romain Georges, et al.
(författare)
-
Material Selection Methodology for an Induction Welding Magnetic Susceptor Based on Hysteresis Losses
- 2022
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons, Ltd. - 1438-1656 .- 1527-2648. ; 24:3
-
Tidskriftsartikel (refereegranskat)abstract
- Induction welding is a fusion bonding process relying on the application of an alternating magnetic field to generate heat at the joining interface. Herein, magnetic hysteresis losses heating elements, called susceptors, which are made of magnetic particles dispersed in a thermoplastic polymer, are investigated. A methodology to identify the parameters influencing the heating rate of the susceptors and to select suitable magnetic particles for their fabrication is proposed. The applied magnetic field amplitude is modeled based on the induction coil geometry and the alternating electrical current introduced to it. Then, properties of the evaluated susceptor particles are obtained through measurements of their magnetic hysteresis. A case study is presented to validate the suitability of the proposed methodology. Particles of iron (Fe), nickel (Ni), and magnetite (Fe3O4) are evaluated as susceptor materials in polypropylene (PP) and polyetheretherketone (PEEK) matrices. Heating rates are predicted using the proposed method, and samples are produced and heated by induction to experimentally verify the results. Good agreement with the predictions is obtained. Ni is the most suitable susceptor material for a PP matrix, while Fe3O4 is preferable for PEEK.
|
|
| 36. |
- Mettan, Xavier, et al.
(författare)
-
Acoustic-Pressure-Assisted Engineering of Aluminum Foams
- 2021
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 23:7
-
Tidskriftsartikel (refereegranskat)abstract
- Shaping metals as a foam modulates their physical properties, enabling attractive applications where lightweight, low thermal conductivity, or acoustic isolation are desirable. Adjusting the size of the bubbles in the foams is particularly relevant for targeted applications. Herein, a method with a detailed theoretical understanding of how to tune the size of the bubbles in aluminum melts in situ via acoustic pressure is provided. The description is in full agreement with the high-rate 3D X-ray radioscopy of the bubble formation. The study with the intriguing results on the effect of foaming on electrical resistivity, Seebeck coefficient, and thermal conductivity from cryogenic to room temperature is complemented. Compared with bulk materials, the investigated foam shows an enhancement in the thermoelectric figure of merit. These results herald promising application of foaming in thermoelectric materials and devices for conversion of thermal energy.
|
|
| 37. |
- Mir, Zahid Mohammad, et al.
(författare)
-
Numerical and Experimental Analysis of Self-Protection in Reinforced Concrete due to Application of Mg–Al–NO2 Layered Double Hydroxides
- 2020
-
Ingår i: Advanced Engineering Materials. - : Wiley-VCH Verlag. - 1438-1656 .- 1527-2648.
-
Tidskriftsartikel (refereegranskat)abstract
- Concrete possesses an intrinsic chloride binding capacity. Chloride ions from the environment bind with the hydrated cementitious phases in the form of bound chlorides. The contribution of chemically bound chlorides toward increasing the service life of concrete structures is vital as they help in slowing down the chloride diffusion in the concrete thereby delaying reinforcement depassivation. The authors attempt to increase the chloride binding capacity of concrete by adding a small amount of Mg–Al–NO2 layered double hydroxides (LDHs) with the objective to delay reinforcement corrosion and by this to considerably extend the service life of concrete structures situated in harsh environments. This study presents numerical and experimental analysis of the action of LDH in concrete. Formation factor is used to determine the effective chloride diffusion coefficient. In addition, the chloride binding isotherms together with Poisson–Nernst–Planck equations are used to model the chloride ingress. A comparable chloride binding is observed for concrete with and without Mg–Al–NO2, depicting only a slight chloride uptake by Mg–Al–NO2. Further investigations are conducted to understand this behavior by studying the stability and chloride entrapping capacity Mg–Al–NO2 in concrete. © 2020 The Authors.
|
|
| 38. |
- Moritz, Juliane, et al.
(författare)
-
Influence of Electron Beam Powder Bed Fusion Process Parameters at Constant Volumetric Energy Density on Surface Topography and Microstructural Homogeneity of a Titanium Aluminide Alloy
- 2023
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons. - 1438-1656 .- 1527-2648. ; 25:15
-
Tidskriftsartikel (refereegranskat)abstract
- In powder bed fusion additive manufacturing, the volumetric energy density E V is a commonly used parameter to quantify process energy input. However, recent results question the suitability of E V as a design parameter, as varying the contributing parameters may yield different part properties. Herein, beam current, scan velocity, and line offset in electron beam powder bed fusion (PBF-EB) of the titanium aluminide alloy TNM–B1 are systematically varied while maintaining an overall constant E V. The samples are evaluated regarding surface morphology, relative density, microstructure, hardness, and aluminum loss due to evaporation. Moreover, the specimens are subjected to two different heat treatments to obtain fully lamellar (FL) and nearly lamellar (NLγ) microstructures, respectively. With a combination of low beam currents, low-to-intermediate scan velocities, and low line offsets, parts with even surfaces, relative densities above 99.9%, and homogeneous microstructures are achieved. On the other hand, especially high beam currents promote the formation of surface bulges and pronounced aluminum evaporation, resulting in inhomogeneous banded microstructures after heat treatment. The results demonstrate the importance of considering the individual parameters instead of E V in process optimization for PBF-EB.
|
|
| 39. |
- Moritz, Juliane, et al.
(författare)
-
Influence of Two-Step Heat Treatments on Microstructure and Mechanical Properties of a β-Solidifying Titanium Aluminide Alloy Fabricated via Electron Beam Powder Bed Fusion
- 2023
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons. - 1438-1656 .- 1527-2648. ; 25:2
-
Tidskriftsartikel (refereegranskat)abstract
- Additive manufacturing technologies, particularly electron beam powder bed fusion (PBF-EB/M), are becoming increasingly important for the processing of intermetallic titanium aluminides. This study presents the effects of hot isostatic pressing (HIP) and subsequent two-step heat treatments on the microstructure and mechanical properties of the TNM-B1 alloy (Ti–43.5Al–4Nb–1Mo–0.1B) fabricated via PBF-EB/M. Adequate solution heat treatment temperatures allow the adjustment of fully lamellar (FL) and nearly lamellar (NL-β) microstructures. The specimens are characterized by optical microscopy and scanning electron microscopy (SEM), X-ray computed tomography (CT), X-ray diffraction (XRD), and electron backscatter diffraction (EBSD). The mechanical properties at ambient temperatures are evaluated via tensile testing and subsequent fractography. While lack-of-fusion defects are the main causes of failure in the as-built condition, the mechanical properties in the heat-treated conditions are predominantly controlled by the microstructure. The highest ultimate tensile strength is achieved after HIP due to the elimination of lack-of-fusion defects. The results reveal challenges originating from the PBF-EB/M process, for example, local variations in chemical composition due to aluminum evaporation, which in turn affect the microstructures after heat treatment. For designing suitable heat treatment strategies, particular attention should therefore be paid to the microstructural characteristics associated with additive manufacturing.
|
|
| 40. |
- Moritz, Juliane, et al.
(författare)
-
Locally Adapted Microstructures in an Additively Manufactured Titanium Aluminide Alloy Through Process Parameter Variation and Heat Treatment
- 2023
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons. - 1438-1656 .- 1527-2648. ; 25:2
-
Tidskriftsartikel (refereegranskat)abstract
- Electron beam powder bed fusion (PBF-EB/M) has been attracting great research interest as a promising technology for additive manufacturing of titanium aluminide alloys. However, challenges often arise from the process-induced evaporation of aluminum, which is linked to the PBF-EB/M process parameters. This study applies different volumetric energy densities during PBF-EB/M processing to deliberately adjust the aluminum contents in additively manufactured Ti–43.5Al–4Nb–1Mo–0.1B (TNM-B1) samples. The specimens are subsequently subjected to hot isostatic pressing (HIP) and a two-step heat treatment. The influence of process parameter variation and heat treatments on microstructure and defect distribution are investigated using optical and scanning electron microscopy, as well as X-ray computed tomography (CT). Depending on the aluminum content, shifts in the phase transition temperatures can be identified via differential scanning calorimetry (DSC). It is confirmed that the microstructure after heat treatment is strongly linked to the PBF-EB/M parameters and the associated aluminum evaporation. The feasibility of producing locally adapted microstructures within one component through process parameter variation and subsequent heat treatment can be demonstrated. Thus, fully lamellar and nearly lamellar microstructures in two adjacent component areas can be adjusted, respectively.
|
|
| 41. |
- Müller, Michael, et al.
(författare)
-
Multimaterial Additive Manufacturing of graded Laves phase reinforced NiAlTa structures by means of Laser Metal Deposition
- 2022
-
Ingår i: Advanced Engineering Materials. - : John Wiley & Sons. - 1438-1656 .- 1527-2648. ; 24:4
-
Tidskriftsartikel (refereegranskat)abstract
- Recently, the Additive Manufacturing (AM) technology Laser Metal Deposition (LMD) has gained a lot of attention for processing crack prone high temperature materials such as nickel based superalloys or intermetallics. This contribution presents a feasibility study on LMD of a graded transition from binary ß-NiAl to Ni50Al42Ta8 with the aim to show the possibility of manufacturing ß-NiAl based structures with a spatially resolved microstructure and subsequently tailored mechanical properties. For achieving this the alloys Ni50Al50 and Ni50Al42Ta8 are co-injected into the process zone and the powder feeding rates are adapted in a layer-wise manner. Due to pre-heating temperatures of up to 1000 °C the transition can be manufactured with high relative density and a low degree of cold cracking. Scanning electron microscopy of the transition zone shows the formation of a fine dendritic microstructure consisting of ß-NiAl dendritic and NiAlTa interdendritic regions. Large area energy dispersive x-ray analysis reveals a gradient in NiAlTa Laves phase content with increasing build height. The observed volume fraction of Laves phase corresponds well to reported values from cast ingots. Finally, hardness measurements along the build-up direction show an increase in hardness from 300 HV0.1 to 680 HV0.1 indicating a tremendous increase in tensile strength.
|
|
| 42. |
- Nan, Beiya, et al.
(författare)
-
Microstructure and Properties of Porous SiC Ceramics Modified by CVI-SiC Nanowires
- 2019
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 21:5
-
Tidskriftsartikel (refereegranskat)abstract
- Sintered porous SiC ceramics are modified with SiC nanowires prepared via chemical vapor infiltration (CVI). SiC nanowires are successfully grown within sintered porous SiC ceramics following vapor-liquid-solid growth. The diameter of the SiC nanowires is in the range of 200 nm-1 mu m, and first decreases with increasing input gas ratio (alpha = 50, 60, 70, and 80) and increases thereafter. The diameter of the nanowires decreases from the surface to the interior areas of the porous SiC ceramics. SiC nanowires effectively improve the mechanical properties of the porous SiC ceramics, and sample Ni-50 has the highest flexural strength of 33.91 MPa and fracture toughness of 0.79 MPa center dot m(1/2), which increases by 90.4% and 49.1% compared to an unmodified sample, respectively. Additionally, the presence of SiC nanowires leads to porous SiC ceramics with altered porosity and microstructure, and higher thermal conductivity. The porous SiC ceramics modified by CVI SiC nanowires satisfy the requirements of gas filtration applications and the pressure drop increases with decreasing apparent porosity. The porous SiC ceramics modified with CVI SiC nanowire has higher permeability than those resulting from the introduction of CVI-SiC matrix or CVD-SiC coating into porous SiC ceramics.
|
|
| 43. |
- Olsson, Oliver, 1993, et al.
(författare)
-
Electrochromic Passive Matrix Display Utilizing Diode-Like Redox Reactions on Indium-Tin-Oxide
- 2024
-
Ingår i: Advanced Engineering Materials. - 1527-2648 .- 1438-1656. ; 26:8
-
Tidskriftsartikel (refereegranskat)abstract
- Recent years have shown many advances in the development of tunable structural colors by combining nanostructures with electrochromic materials. One main goal is to develop energy saving color displays that rely on ambient light instead of being emissive. However, all displays need to be pixelated to show arbitrary images and few studies have addressed the challenge of preparing and controlling individual electrochromic pixels. Herein, a very simple method to reach this milestone by using passive matrix addressing is presented, which requires no additional electronic components in the pixels. It is shown that the common transparent conductor indium tin oxide (ITO) in non-aqueous electrolytes exhibits the diode-like behavior (threshold in voltage in relation to current and coloration) necessary to prevent significant cross-talk between pixels. The chemical nature of the redox activity that enables this behavior is attributed to omnipresent oxygen and the formation of superoxide ions. Additionally, it is shown that a gel-like electrolyte can be prepared by optical lithography, which makes the concept compatible with patterning of pixels at high resolution. This method for preparing pixelated displays should be compatible with practically any type of electrochromic surface in both reflective and transmissive configurations. Also, the counter electrode maintains excellent transparency since it simply consists of ITO. The results should prove very useful as the research field of tunable structural colors moves from proof-of-concept to real devices. A method for realizing pixelated electrochromic devices using passive matrix addressing is presented. This is achieved simply by using indium-tin-oxide (ITO) as the counter electrode, which creates a diode-like current response in a stable electrolyte.image (c) 2024 WILEY-VCH GmbH
|
|
| 44. |
- Pranzas, P. Klaus, et al.
(författare)
-
Characterization of Hydrogen Storage Materials and Systems with Photons and Neutrons
- 2011
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1527-2648 .- 1438-1656. ; 13:8, s. 730-736
-
Tidskriftsartikel (refereegranskat)abstract
- Complex hydrides are very promising candidates for future light-weight solid state hydrogen storage materials. The present work illustrates detailed characterization of such novel hydride materials on different size scales by the use of synchrotron radiation and neutrons. The comprehensive analysis of such data leads to a deep understanding of the ongoing processes and mechanisms. The reaction pathways during hydrogen desorption and absorption are identified by in situ X-ray diffraction (XRD). Function and size of additive phases are estimated using X-ray absorption spectroscopy (XAS) and anomalous small-angle X-ray scattering (ASAXS). The structure of the metal hydride matrix is characterized using (ultra) small-angle neutron scattering (SANS/USANS). The hydrogen distribution in tanks filled with metal hydride material is studied with neutron computerized tomography (NCT). The results obtained by the different analysis methods are summarized in a final structural model. The complementary information obtained by these different methods is essential for the understanding of the various sorption processes in light metal hydrides and hydrogen storage tanks.
|
|
| 45. |
- Saarimäki, Jonas, et al.
(författare)
-
Grain Size Depending Dwell-Fatigue Crack Growth in Inconel 718
- 2018
-
Ingår i: Advanced Engineering Materials. - : Wiley-VCH Verlagsgesellschaft. - 1438-1656 .- 1527-2648.
-
Tidskriftsartikel (refereegranskat)abstract
- Inconel 718 is a commonly used superalloy for turbine discs in the gas turbine industry. Turbine discs are normally subjected to dwell-fatigue as a result of long constant load cycles. Dwell-times have been shown to give rise to increased crack propagation rates in superalloys at elevated temperatures. Dwell-time crack propagation behavior in Inconel 718 has been tested at 550 °C using Kb test samples with 2160 s dwell-times at maximum load and “pure fatigue” tests. The dwell-time effect has been studied for differently processed Inconel 718, that is, fine grained bar, grain enlarged bar, and cast material. This has been done in order to investigate the effect of grain size on crack propagation. Microstructure characterization is conducted using scanning electron microscopy techniques such as electron channeling contrast imaging and electron backscatter diffraction. Time dependent crack propagation rates are strongly affected by grain size. Propagation rates increase with decreasing grain size, whereas crack tip blunting increased with increasing grain size.
|
|
| 46. |
- Schröder, Vincent R.F., et al.
(författare)
-
Using Combinatorial Inkjet Printing for Synthesis and Deposition of Metal Halide Perovskites in Wavelength-Selective Photodetectors
- 2022
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 24:4
-
Tidskriftsartikel (refereegranskat)abstract
- Metal halide perovskites have received great attention in recent years, predominantly due to the high performance of perovskite solar cells. The versatility of the material, which allows the tunability of the bandgap, has led to its use in light-emitting diodes, photo, and X-ray detectors, among other optoelectronic device applications. Specifically in photodetectors, the tunability of the bandgap allows fabrication of spectrally selective devices. Utilizing a combinatorial inkjet printing approach, multiple perovskite compositions absorbing at specific wavelengths in a single printing step are fabricated. The drop-on-demand capabilities of inkjet printing enable the deposition of inks in a precise ratio to produce specific perovskite compositions in the printed thin film. By controlling the halide ratio in the compositions, a mixed halide gradient ranging from pure MAPbI3 via MAPbBr3 to MAPbCl3 is produced. The tunability in the absorption onset from 410 to 790 nm is demonstrated, covering the whole visible spectrum, with a precision of 8 nm steps for MAPb(BrxCl1−x)3 compositions. From this range of mixed halide perovskites, photodetectors which show spectral selectivity corresponding to the measured absorption onset are demonstrated, paving the way for use in a printed visible light spectrometer without the need for a dispersion element.
|
|
| 47. |
|
|
| 48. |
- Sokkalingam, Rathinavelu, et al.
(författare)
-
Additive Manufacturing of CoCrFeMnNi High-Entropy Alloy/AISI 316L Stainless Steel Bimetallic Structures
- 2022
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648.
-
Tidskriftsartikel (refereegranskat)abstract
- CoCrFeMnNi high-entropy alloy (HEA)/AISI 316L stainless steel bimetals were additively fabricated using selective laser melting (SLM). The bimetal structure comprises three regions, i.e., CoCrFeMnNi-HEA, AISI 316L stainless steel, and an interface between CoCrFeMnNi-HEA, AISI 316L stainless steel. SLM processing results in the formation of columnar grains extending over many built layers epitaxially in a preferential growth direction. The Vickers microhardness ranges mainly between 250 and 275 HV0.5 in all three observed regions. In addition, only a marginal variation in tensile strength is observed between the CoCrFeMnNi-HEA, AISI 316L stainless steel, and the CoCrFeMnNi-HEA/AISI 316L stainless steel bimetal. The unique higher work hardening behavior of the CoCrFeMnNi-HEA prevents failure along the CoCrFeMnNi-HEA side in the bimetallic structure during plastic deformation. The CoCrFeMnNi-HEA shows higher pitting susceptibility than the AISI 316L stainless steel in the bimetallic structure due to its lower pitting potential. Further, the presence of pores and lack of fusion spots further decreases the pitting resistance of the CoCrFeMnNi-HEA. Hence, the bimetal is prone to more preferential corrosion attack along the CoCrFeMnNi-HEA side due to its anodic behavior and defects.
|
|
| 49. |
- Stenqvist, Torkel, et al.
(författare)
-
3D X-Ray Diffraction Characterization of Grain Growth and Recrystallization in Rolled Braze Clad Aluminum Sheet
- 2021
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 23:11
-
Tidskriftsartikel (refereegranskat)abstract
- Braze clad on aluminum (Al) sheets has enabled fast and convenient brazing assembly of complex heat exchangers. However, there are details in the brazing process that are not fully understood. Herein, 3D X-ray diffraction (3DXRD) is used to investigate the grain position, size, and orientation before and after controlled atmosphere brazing (CAB). The outcomes are presented as maps of center-of-mass positions with relative grain size distribution and color-coded grain orientations. The results show that, for braze clad Al sheets exposed to CAB simulation, it is possible to distinguish grains from the solidified Al-Si alloy from those in the core Al alloy. It is also possible to distinguish new grains obtained through recrystallization during CAB. Hence, the study shows that stretching of the rolled Al sheet by 6% provides enough stored energy in the core material so that recrystallization occurs during CAB and, in addition, provides conditions for Al-Si alloy grain growth into the core material. While the phenomenon is well known, it is poorly understood for processes in connection with brazing of mechanically formed Al alloy components in heat exchanger assemblies, and these results demonstrate the potential for gaining deeper insights through 3DXRD.
|
|
| 50. |
- Strondl, A., et al.
(författare)
-
Effect of Processing on Microstructure and Physical Properties of Three Nickel-Based Superalloys with Different Hardening Mechanisms
- 2012
-
Ingår i: Advanced Engineering Materials. - : Wiley. - 1527-2648 .- 1438-1656. ; 14:7, s. 427-438
-
Tidskriftsartikel (refereegranskat)abstract
- The nickel-based superalloys Inconel alloy 600, Udimet alloy 720, and Inconel alloy 718 were produced by electron beam melting (EBM), casting, and directional solidification (DS). The distance between dendrites and the size of the precipitates indicated the difference in solidification rates between the three processes. In this study, the solidification rate was fastest with EBM, closely followed by casting, whereas it was much slower with DS. In the directional solidified materials the direction was the fastest and thus, preferred growth direction. The EBM samples show a sharp (001)[100] texture in the building direction and in the two scanning directions of the electron beam. Macrosegregation was observed in some cast and directionally solidified samples, but not in the EBM samples. The melting temperatures are in good agreement with literature and the narrow melting interval of IN600 compare to UD720 and IN718 might reduce the risk of incipient melting during EBM processing. Porosity was observed in the EBM samples and the reasons are discussed. However, EBM seems to be a feasible process route to produce nickel-based superalloys with well-defined texture, no macrosegregation and a rapidly solidified microstructure.
|
|
