@article{33656, author = {{Wang, Mengying and Ranjbar, Ahmad and Kühne, Thomas and Belosludov, Rodion V. and Kawazoe, Yoshiyuki and Liang, Yunye}}, issn = {{0008-6223}}, journal = {{Carbon}}, keywords = {{General Chemistry, General Materials Science}}, pages = {{370--378}}, publisher = {{Elsevier BV}}, title = {{{A theoretical investigation of topological phase modulation in carbide MXenes: Role of image potential states}}}, doi = {{10.1016/j.carbon.2021.05.026}}, volume = {{181}}, year = {{2021}}, } @article{33659, abstract = {{Abstract We performed a virtual materials screening to identify promising topological materials for photocatalytic water splitting under visible light irradiation. Topological compounds were screened based on band gap, band edge energy, and thermodynamics stability criteria. In addition, topological types for our final candidates were computed based on electronic structures calculated usingthe hybrid density functional theory including exact Hartree–Fock exchange. Our final list contains materials which have band gaps between 1.0 and 2.7 eV in addition to band edge energies suitable for water oxidation and reduction. However, the topological types of these compounds calculated with the hybrid functional differ from those reported previously. To that end, we discuss the importance of computational methods for the calculation of atomic and electronic structures in materials screening processes.}}, author = {{Ranjbar, Ahmad and Mirhosseini, Hossein and Kühne, Thomas}}, issn = {{2515-7639}}, journal = {{Journal of Physics: Materials}}, keywords = {{Condensed Matter Physics, General Materials Science, Atomic and Molecular Physics, and Optics}}, number = {{1}}, publisher = {{IOP Publishing}}, title = {{{On topological materials as photocatalysts for water splitting by visible light}}}, doi = {{10.1088/2515-7639/ac363d}}, volume = {{5}}, year = {{2021}}, } @article{33895, abstract = {{Heat-assisted forming processes are becoming increasingly important in the manufacturing of sheet metal parts for body-in-white applications. However, the non-isothermal nature of these processes leads to challenges in evaluating the forming limits, since established methods such as Forming Limit Curves (FLCs) only allow the assessment of critical forming strains for steady temperatures. For this reason, a temperature-dependent extension of the well-established GISSMO (Generalized Incremental Stress State Dependent Damage Model) fracture indicator framework is developed by the authors to predict forming failures under non-isothermal conditions. In this paper, a general approach to combine several isothermal FLCs within the temperature-extended GISSMO model into a temperature-dependent forming limit surface is investigated. The general capabilities of the model are tested in a coupled thermo-mechanical FEA using the example of warm forming of an AA5182-O sheet metal cross-die cup. The obtained results are then compared with state of the art of evaluation methods. By taking the strain and temperature path into account, GISSMO predicts greater drawing depths by up to 20% than established methods. In this way the forming and so the lightweight potential of sheet metal parts can by fully exploited. Moreover, the risk and locus of failure can be evaluated directly on the part geometry by a contour plot. An additional advantage of the GISSMO model is the applicability for low triaxialities as well as the possibility to predict the materials behavior beyond necking up to ductile fracture.}}, author = {{Camberg, Alan Adam and Erhart, Tobias and Tröster, Thomas}}, issn = {{1996-1944}}, journal = {{Materials}}, keywords = {{General Materials Science}}, number = {{17}}, publisher = {{MDPI AG}}, title = {{{A Generalized Stress State and Temperature Dependent Damage Indicator Framework for Ductile Failure Prediction in Heat-Assisted Forming Operations}}}, doi = {{10.3390/ma14175106}}, volume = {{14}}, year = {{2021}}, } @article{34087, author = {{Knust, Steffen and Ruhm, Lukas and Kuhlmann, Andreas and Meinderink, Dennis and Bürger, Julius and Lindner, Jörg and de los Arcos de Pedro, Maria Teresa and Grundmeier, Guido}}, issn = {{0377-0486}}, journal = {{Journal of Raman Spectroscopy}}, keywords = {{Spectroscopy, General Materials Science}}, number = {{7}}, pages = {{1237--1245}}, publisher = {{Wiley}}, title = {{{In situ backside Raman spectroscopy of zinc oxide nanorods in an atmospheric‐pressure dielectric barrier discharge plasma}}}, doi = {{10.1002/jrs.6123}}, volume = {{52}}, year = {{2021}}, } @article{47963, abstract = {{Nonlinear and quantum optical devices based on periodically-poled thin film lithium niobate (PP-TFLN) have gained considerable interest lately, due to their significantly improved performance as compared to their bulk counterparts. Nevertheless, performance parameters such as conversion efficiency, minimum pump power, and spectral bandwidth strongly depend on the quality of the domain structure in these PP-TFLN samples, e.g., their homogeneity and duty cycle, as well as on the overlap and penetration depth of domains with the waveguide mode. Hence, in order to propose improved fabrication protocols, a profound quality control of domain structures is needed that allows quantifying and thoroughly analyzing these parameters. In this paper, we propose to combine a set of nanometer-to-micrometer-scale imaging techniques, i.e., piezoresponse force microscopy (PFM), second-harmonic generation (SHG), and Raman spectroscopy (RS), to access the relevant and crucial sample properties through cross-correlating these methods. Based on our findings, we designate SHG to be the best-suited standard imaging technique for this purpose, in particular when investigating the domain poling process in x-cut TFLNs. While PFM is excellently recommended for near-surface high-resolution imaging, RS provides thorough insights into stress and/or defect distributions, as associated with these domain structures. In this context, our work here indicates unexpectedly large signs for internal fields occurring in x-cut PP-TFLNs that are substantially larger as compared to previous observations in bulk LN.}}, author = {{Reitzig, Sven and Rüsing, Michael and Zhao, Jie and Kirbus, Benjamin and Mookherjea, Shayan and Eng, Lukas M.}}, issn = {{2073-4352}}, journal = {{Crystals}}, keywords = {{Inorganic Chemistry, Condensed Matter Physics, General Materials Science, General Chemical Engineering}}, number = {{3}}, publisher = {{MDPI AG}}, title = {{{“Seeing Is Believing”—In-Depth Analysis by Co-Imaging of Periodically-Poled X-Cut Lithium Niobate Thin Films}}}, doi = {{10.3390/cryst11030288}}, volume = {{11}}, year = {{2021}}, } @article{47964, abstract = {{In the last two decades, variably doped strontium barium niobate (SBN) has attracted a lot of scientific interest mainly due to its specific non-linear optical response. Comparably, the parental compound, i.e., undoped SBN, appears to be less studied so far. Here, two different cuts of single-crystalline nominally pure strontium barium niobate in the composition Sr0.61Ba0.39Nb2O6 (SBN61) are comprehensively studied and analyzed with regard to their photoconductive responses. We present conductance measurements under systematically varied illumination conditions along either the polar z-axis or perpendicular to it (x-cut). Apart from a pronounced photoconductance (PC) already under daylight and a large effect upon super-bandgap illumination in general, we observe (i) distinct spectral features when sweeping the excitation wavelength over the sub-bandgap region as then discussed in the context of deep and shallow trap states, (ii) extremely slow long-term relaxation for both light-on and light-off transients in the range of hours and days, (iii) a critical dependence of the photoresponse on the pre-illumination history of the sample, and (iv) a current–voltage hysteresis depending on both the illumination and the electrical-measurement conditions in a complex manner.}}, author = {{Beyreuther, Elke and Ratzenberger, Julius and Roeper, Matthias and Kirbus, Benjamin and Rüsing, Michael and Ivleva, Liudmila I. and Eng, Lukas M.}}, issn = {{2073-4352}}, journal = {{Crystals}}, keywords = {{Inorganic Chemistry, Condensed Matter Physics, General Materials Science, General Chemical Engineering}}, number = {{7}}, publisher = {{MDPI AG}}, title = {{{Photoconduction of Polar and Nonpolar Cuts of Undoped Sr0.61Ba0.39Nb2O6 Single Crystals}}}, doi = {{10.3390/cryst11070780}}, volume = {{11}}, year = {{2021}}, } @article{53268, author = {{Soleymani, Mohammad and Santamaria, Ignacio and Schreier, Peter J.}}, issn = {{2169-3536}}, journal = {{IEEE Access}}, keywords = {{General Engineering, General Materials Science, General Computer Science}}, pages = {{96948--96963}}, publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}}, title = {{{Distributed Algorithms for Spectral and Energy-Efficiency Maximization of K-User Interference Channels}}}, doi = {{10.1109/access.2021.3094976}}, volume = {{9}}, year = {{2021}}, } @article{40573, author = {{Wang, Huize and Delacroix, Simon and Osswald, Oliver and Anderson, Mackenzie and Heil, Tobias and Lepre, Enrico and Lopez Salas, Nieves and Kaner, Richard B. and Smarsly, Bernd and Strauss, Volker}}, issn = {{0008-6223}}, journal = {{Carbon}}, keywords = {{General Chemistry, General Materials Science}}, pages = {{500--510}}, publisher = {{Elsevier BV}}, title = {{{Laser-carbonization: Peering into the formation of micro-thermally produced (N-doped)carbons}}}, doi = {{10.1016/j.carbon.2021.01.145}}, volume = {{176}}, year = {{2021}}, } @article{40572, author = {{Ilic, Ivan K. and Lepre, Enrico and Lopez Salas, Nieves}}, issn = {{1944-8244}}, journal = {{ACS Applied Materials & Interfaces}}, keywords = {{General Materials Science}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Caffeine-Derived Noble Carbons as Ball Milling-Resistant Cathode Materials for Lithium-Ion Capacitors}}}, doi = {{10.1021/acsami.1c06013}}, year = {{2021}}, } @article{40568, abstract = {{The search for metal-free and visible light-responsive materials for photocatalytic applications has attracted the interest of not only academics but also the industry in the last decades. Since graphitic carbon nitride (g-C3N4) was first reported as a metal-free photocatalyst, this has been widely investigated in different light-driven reactions. However, the high recombination rate, low electrical conductivity, and lack of photoresponse in most of the visible range have elicited the search for alternatives. In this regard, a broad family of carbon nitride (CxNy) materials was anticipated several decades ago. However, the attention of the researchers in these materials has just been awakened in the last years due to the recent success in the syntheses of some of these materials (i.e., C3N3, C2N, C3N, and C3N5, among others), together with theoretical simulations pointing at the excellent physico-chemical properties (i.e., crystalline structure and chemical morphology, electronic configuration and semiconducting nature, or high refractive index and hardness, among others) and optoelectronic applications of these materials. The performance of CxNy, beyond C3N4, has been barely evaluated in real applications, including energy conversion, storage, and adsorption technologies, and further work must be carried out, especially experimentally, in order to confirm the high expectations raised by simulations and theoretical calculations. Herein, we have summarized the scarce literature related to recent results reporting the synthetic routes, structures, and performance of these materials as photocatalysts. Moreover, the challenges and perspectives at the forefront of this field using CxNy materials are disclosed. We aim to stimulate the research of this new generation of CxNy-based photocatalysts, beyond C3N4, with improved photocatalytic efficiencies by harnessing the striking structural, electronic, and optical properties of this new family of materials.}}, author = {{Lopez Salas, Nieves and Albero, Josep}}, issn = {{2296-8016}}, journal = {{Frontiers in Materials}}, keywords = {{Materials Science (miscellaneous)}}, publisher = {{Frontiers Media SA}}, title = {{{CxNy: New Carbon Nitride Organic Photocatalysts}}}, doi = {{10.3389/fmats.2021.772200}}, volume = {{8}}, year = {{2021}}, } @article{40570, abstract = {{Copper- and nitrogen-doped carbonaceous materials, obtained by a simple synthetic procedure are highly efficient and fast catalysts for the oxygen reduction reaction. It is shown, that Cu(i) containing materials perform with faster reaction kinetics.}}, author = {{Kossmann, Janina and Ortíz Sánchez-Manjavacas, María Luz and Zschiesche, Hannes and Tarakina, Nadezda V. and Antonietti, Markus and Albero, Josep and Lopez Salas, Nieves}}, issn = {{2050-7488}}, journal = {{Journal of Materials Chemistry A}}, keywords = {{General Materials Science, Renewable Energy, Sustainability and the Environment, General Chemistry}}, number = {{11}}, pages = {{6107--6114}}, publisher = {{Royal Society of Chemistry (RSC)}}, title = {{{CuII/CuI decorated N-doped carbonaceous electrocatalysts for the oxygen reduction reaction}}}, doi = {{10.1039/d1ta09459a}}, volume = {{10}}, year = {{2021}}, } @article{34227, abstract = {{In order to reduce the fuel consumption and consequently the greenhouse emissions, the automotive industry is implementing lightweight constructions in the body in white production. As a result, the use of aluminum alloys is continuously increasing. Due to poor weldability of aluminum in combination with other materials, mechanical joining technologies like clinching are increasingly used. In order to predict relevant characteristics of clinched joints and to ensure the reliability of the process, it is simulated numerically during product development processes. In this regard the predictive accuracy of the simulated process highly depends on the implemented friction model. In particular, the frictional behavior between the sheet metals affects the geometrical formation of the clinched joint significantly. This paper presents a testing method, which enables to determine the frictional coefficients between sheet metal materials for the simulation of clinching processes. For this purpose, the correlation of interface pressure and the relative velocity between aluminum sheets in clinching processes is investigated using numerical simulation. Furthermore, the developed testing method focuses on the specimen geometry as well as the reproduction of the occurring friction conditions between two sheet metal materials in clinching processes. Based on a methodical approach the test setup is explained and the functionality of the method is proven by experimental tests using sheet metal material EN AW6014.}}, author = {{Rossel, Moritz Sebastian and Böhnke, Max and Bielak, Christian Roman and Bobbert, Mathias and Meschut, Gerson}}, issn = {{1662-9795}}, journal = {{Key Engineering Materials}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, pages = {{81--88}}, publisher = {{Trans Tech Publications, Ltd.}}, title = {{{Development of a Method for the Identification of Friction Coefficients in Sheet Metal Materials for the Numerical Simulation of Clinching Processes}}}, doi = {{10.4028/www.scientific.net/kem.883.81}}, volume = {{883}}, year = {{2021}}, } @inproceedings{30675, abstract = {{In many areas of product manufacturing constructions consist of individual components and metal sheets that are joined together to form complex structures. A simple and industrial common method for joining dissimilar and coated materials is clinching. During the joining process and due to the service load cracks can occur in the area of the joint, propagate due to cyclic loading and consequently lead to structural failure. For the prevention of these damage cases, first of all knowledge about the fracture mechanical material parameters regarding the original material state of the sheet metals used within the clinching process are essential.Within the scope of this paper experimental and numerical preliminary investigations regarding the fracture mechanical behavior of sheet metals used within the clinching process are presented. Due to the low thickness of 1.5 mm of the material sheets, the development of a new specimen is necessary to determine the crack growth rate curve including the fracture mechanical parameters like the threshold against crack growth ΔKI,th and the fracture toughness KIC of the base material HCT590X. For the experimental determination of the crack growth rate curve the numerical calculation of the geometry factor function as well as the calibration function of this special specimen are essential. After the experimental validation of the numerically determined calibration function, crack growth rate curves are determined for the stress ratios R = 0.1 and R = 0.3 to examine the mean stress sensitivity. In addition, the different rolling directions of 0° and 90° in relation to the initial crack are taken into account in order to investigate the influence of the anisotropy due to rolling.}}, author = {{Weiß, Deborah and Schramm, Britta and Kullmer, Gunter}}, booktitle = {{Key Engineering Materials}}, issn = {{1662-9795}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, location = {{online}}, pages = {{127--132}}, publisher = {{Trans Tech Publications, Ltd.}}, title = {{{Numerical and Experimental Fracture Mechanical Investigations of Clinchable Sheet Metals Made of HCT590X}}}, doi = {{10.4028/www.scientific.net/kem.883.127}}, volume = {{883}}, year = {{2021}}, } @article{39383, abstract = {{Zinc oxide nanoparticles (ZnO NP) used for the channel region in inverted coplanar setup in Thin Film Transistors (TFT) were the focus of this study. The regions between the source electrode and the ZnO NP and the drain electrode were under investigation as they produce a Schottky barrier in metal-semiconductor interfaces. A more general Thermionic emission theory must be evaluated: one that considers both metal/semiconductor interfaces (MSM structures). Aluminum, gold, and nickel were used as metallization layers for source and drain electrodes. An organic-inorganic nanocomposite was used as a gate dielectric. The TFTs transfer and output characteristics curves were extracted, and a numerical computational program was used for fitting the data; hence information about Schottky Barrier Height (SBH) and ideality factors for each TFT could be estimated. The nickel metallization appears with the lowest SBH among the metals investigated. For this metal and for higher drain-to-source voltages, the SBH tended to converge to some value around 0.3 eV. The developed fitting method showed good fitting accuracy even when the metallization produced different SBH in each metal-semiconductor interface, as was the case for gold metallization. The Schottky effect is also present and was studied when the drain-to-source voltages and/or the gate voltage were increased.}}, author = {{Kaufmann, Ivan Rodrigo and Zerey, Onur and Meyers, Thorsten and Reker, Julia and Vidor, Fábio and Hilleringmann, Ulrich}}, issn = {{2079-4991}}, journal = {{Nanomaterials}}, keywords = {{General Materials Science, General Chemical Engineering}}, number = {{5}}, publisher = {{MDPI AG}}, title = {{{A Study about Schottky Barrier Height and Ideality Factor in Thin Film Transistors with Metal/Zinc Oxide Nanoparticles Structures Aiming Flexible Electronics Application}}}, doi = {{10.3390/nano11051188}}, volume = {{11}}, year = {{2021}}, } @article{40434, author = {{Klement, Philip and Dehnhardt, Natalie and Dong, Chuan-Ding and Dobener, Florian and Bayliff, Samuel and Winkler, Julius and Hofmann, Detlev M. and Klar, Peter J. and Schumacher, Stefan and Chatterjee, Sangam and Heine, Johanna}}, issn = {{0935-9648}}, journal = {{Advanced Materials}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, number = {{23}}, publisher = {{Wiley}}, title = {{{Atomically Thin Sheets of Lead‐Free 1D Hybrid Perovskites Feature Tunable White‐Light Emission from Self‐Trapped Excitons}}}, doi = {{10.1002/adma.202100518}}, volume = {{33}}, year = {{2021}}, } @article{34226, abstract = {{The increasing use of multi-material constructions lead to a continuous increase in the use of mechanical joining techniques due to the wide range of joining possibilities as well as the high load-bearing capacities of the joints. Nevertheless, the currently rigid tool systems are not able to react to changing boundary conditions, like changing the material-geometry-combination. Therefore research work is crucial with regard to versatile joining systems. In this paper, a new approach for a versatile self-piercing riveting process considering the joining system as well as the auxiliary joining part is presented.}}, author = {{Kappe, Fabian and Bobbert, Mathias and Meschut, Gerson}}, issn = {{1662-9795}}, journal = {{Key Engineering Materials}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, pages = {{3--10}}, publisher = {{Trans Tech Publications, Ltd.}}, title = {{{New Approach for Versatile Self Piercing Riveting: Joining System and Auxiliary Part}}}, doi = {{10.4028/www.scientific.net/kem.883.3}}, volume = {{883}}, year = {{2021}}, } @article{41511, author = {{Hein, Maxwell and Hoyer, Kay-Peter and Schaper, Mirko}}, issn = {{0933-5137}}, journal = {{Materialwissenschaft und Werkstofftechnik}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science}}, number = {{7}}, pages = {{703--716}}, publisher = {{Wiley}}, title = {{{Additively processed TiAl6Nb7 alloy for biomedical applications}}}, doi = {{10.1002/mawe.202000288}}, volume = {{52}}, year = {{2021}}, } @article{41506, abstract = {{Processing aluminum alloys employing powder bed fusion of metals (PBF-LB/M) is becoming more attractive for the industry, especially if lightweight applications are needed. Unfortunately, high-strength aluminum alloys such as AA7075 are prone to hot cracking during PBF-LB/M, as well as welding. Both a large solidification range promoted by the alloying elements zinc and copper and a high thermal gradient accompanied with the manufacturing process conditions lead to or favor hot cracking. In the present study, a simple method for modifying the powder surface with titanium carbide nanoparticles (NPs) as a nucleating agent is aimed. The effect on the microstructure with different amounts of the nucleating agent is shown. For the aluminum alloy 7075 with 2.5 ma% titanium carbide nanoparticles, manufactured via PBF-LB/M, crack-free samples with a refined microstructure having no discernible melt pool boundaries and columnar grains are observed. After using a two-step ageing heat treatment, ultimate tensile strengths up to 465 MPa and an 8.9% elongation at break are achieved. Furthermore, it is demonstrated that not all nanoparticles used remain in the melt pool during PBF-LB/M.}}, author = {{Heiland, Steffen and Milkereit, Benjamin and Hoyer, Kay-Peter and Zhuravlev, Evgeny and Kessler, Olaf and Schaper, Mirko}}, issn = {{1996-1944}}, journal = {{Materials}}, keywords = {{General Materials Science}}, number = {{23}}, publisher = {{MDPI AG}}, title = {{{Requirements for Processing High-Strength AlZnMgCu Alloys with PBF-LB/M to Achieve Crack-Free and Dense Parts}}}, doi = {{10.3390/ma14237190}}, volume = {{14}}, year = {{2021}}, } @article{41512, author = {{Andreiev, Anatolii and Hoyer, Kay-Peter and Dula, Dimitri and Hengsbach, Florian and Grydin, Olexandr and Frolov, Yaroslav and Schaper, Mirko}}, issn = {{0921-5093}}, journal = {{Materials Science and Engineering: A}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science}}, publisher = {{Elsevier BV}}, title = {{{Laser beam melting of functionally graded materials with application-adapted tailoring of magnetic and mechanical performance}}}, doi = {{10.1016/j.msea.2021.141662}}, volume = {{822}}, year = {{2021}}, } @article{41510, author = {{Pramanik, Sudipta and Andreiev, Anatolii and Hoyer, Kay-Peter and Schaper, Mirko}}, issn = {{0142-1123}}, journal = {{International Journal of Fatigue}}, keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering, Mechanics of Materials, General Materials Science, Modeling and Simulation}}, publisher = {{Elsevier BV}}, title = {{{Quasi in-situ analysis of fracture path during cyclic loading of double-edged U notched additively manufactured FeCo alloy}}}, doi = {{10.1016/j.ijfatigue.2021.106498}}, volume = {{153}}, year = {{2021}}, }