TY - CONF A1 - Ferrari, Bruno T1 - Microstructural evolution of PBF-LB/M Inconel 718 during solution-aging heat treatments - an in-situ x-ray diffraction study N2 - Inconel 718 (IN718) is a traditional age-hardenable nickel-based alloy that has been increasingly processed by additive manufacturing (AM) in recent years. In the as-solidified condition, IN718 exhibits chemical segregation and the undesired Laves phase, requiring a solution annealing (SA) prior to aging. The material produced by AM does not respond to the established thermal routines in the same way as conventionally produced IN718, and there is still no consensus on which routine yields optimal results. This work aims to provide a fundamental understanding of the heat treatment (HT) response by continuously monitoring the microstructural evolution during SA via time-resolved synchrotron x-ray diffraction, complemented by ex-situ scanning electron microscopy (SEM). The samples were produced by laser powder bed fusion to a geometry of 10x20x90 mm³, from which Ø1x5 mm³ cylindric specimens were extracted. Two different scanning strategies – incremental 67° rotations, Rot, and alternating 0°/67° tracks, Alt – were used, leading to two different as-built conditions. 1-hour SAs were carried out in the beamline ID22 of the ESRF at 50 KeV. Two SA temperatures, SA1 = 1020 °C, and SA2 = 1080 °C were tested for each scanning strategy. Data were processed using the software PDIndexer. In the as-built state, all samples showed typical subgrain columnar cell structures with predominant Nb/Mo segregation and Laves phase at the cell walls, as seen by SEM. The Alt scan induced higher intensity on the Laves peaks than the Rot scan, suggesting a greater content of Laves. Chemical homogenization in the SA was largely achieved during the heating ramp (Fig. 1). SA2 eliminated the Laves peaks just before reaching 1080 °C, and mitigated differences between Rot and Alt samples. On the other hand, SA1 induced the precipitation of the generally detrimental δ phase, also observed by SEM. Furthermore, the Rot scan showed higher δ peak intensities than the Alt scan, indicating a higher content of δ in the latter. No signs of recrystallization were observed in any of the investigated SAs. T2 - FEMS EUROMAT 2023 CY - Frankfurt a. M., Germany DA - 03.09.2023 KW - Additive Manufacturing KW - X-Ray Diffraction KW - Inconel 718 KW - Heat Treatments KW - Microstructure PY - 2023 AN - OPUS4-58392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Santos Baltieri, Ricardo T1 - Luminescence Thermometry in Pure TeO₂ Glasses Doped with Er3+/Yb3+ and Eu3+: Remote Sensing Capability Across the Biological Temperature Range N2 - The development of non-contact and remote temperature sensors based on rare-earth (RE3+)-doped glasses is crucial for emerging applications in biomedical diagnostics and microscale thermal monitoring. In this study, we explore the fundamental thermometric properties of pure tellurite (TeO2) glasses doped with either Er3+/Yb3+ or Eu3+ ions in a wide range of temperature. The Er3+/Yb3+-co-doped system was analyzed through upconversion emission thermometry, particularly involving thermally coupled levels 2H11/2 and 4S3/2. The intensity ratio between these levels exhibits a clear temperature dependence from 100 K to 530 K, with an inversion near 160 K and optimal sensitivity above 250 K. At 300 K, the relative sensitivity (SR) reached 1.1% K−1, and the absolute sensitivity peaked at 6.5 × 10−3 K−1 at 460 K. Figure on the left is the Er3+ upconversion luminescence dependency on temperature, in the center is the excitation spectra of Eu3+ with temperature, and on the right is the comparison between calculated and measured temperature for Eu3+ samples. In parallel, the excitation spectra of Eu3+-doped TeO2 glasses were acquired from 100 K to 520 K, revealing three thermally responsive spectral regions. These transitions exhibited temperature-dependent intensity inversions, enabling the use of excitation-based thermometry. Notably, one of the regions provided the most accurate temperature predictions, with a relative sensitivity of 0.5% K−1 at 300 K. Both systems benefit from the high optical transparency, chemical stability, and low phonon energy of pure TeO2 glass, making them ideal candidates for remote sensing platforms, such as fiber-optic tips or implantable probes. While the Er3+/Yb3+ system provides robust upconversion emission for conventional thermometry, the Eu3+ system introduces an innovative excitation-based strategy, broadening the applicability of RE3+-doped tellurite glasses for optical thermometry. Acknowledgements This work was supported by the São Paulo Research Foundation (FAPESP – N. 2020/11038-2, 2023/05994-6, 2024/04675-7) and National Council for Scientific and Technological Development (CNPq - 304718/2023-8). T2 - Shift 2025 Conference CY - Tenerife, Spain DA - 13.10.2025 KW - Lanthanide KW - Optical thermometry KW - Energy conversion PY - 2025 AN - OPUS4-65195 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Darvishi Kamachali, Reza T1 - Melting upon Coalescence of Solid Nanoparticles N2 - The large surface-to-volume ratio of nanoparticles is understood to be the source of many interesting phenomena. The melting temperature of nanoparticles is shown to dramatically reduce compared to bulk material. Yet, at temperatures below this reduced melting point, a liquid-like atomic arrangement on the surface of nanoparticles is still anticipated to influence its properties. To understand such surface effects, here, we study the coalescence of Au nanoparticles of various sizes using molecular dynamics simulations. Analysis of the potential energy and Lindemann index distribution across the nanoparticles reveals that high-energy, high-mobility surface atoms can enable the coalescence of nanoparticles at temperatures much lower than their corresponding melting point. The smaller the nanoparticles, the larger the difference between their melting and coalescence temperatures. For small enough particles and/or elevated enough temperatures, we found that the coalescence leads to a melting transition of the two nominally solid nanoparticles, here discussed in relation to the heat released due to the surface reduction upon the coalescence and the size dependence of latent heat. Such discontinuous melting transitions can lead to abrupt changes in the properties of nanoparticles, important for their applications at intermediate temperatures. KW - Nanoparticles KW - Molecular Dynamics KW - Surface-induced Melting PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552183 DO - https://doi.org/10.3390/solids3020025 VL - 3 IS - 2 SP - 361 EP - 373 PB - MDPI AN - OPUS4-55218 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Darvishi Kamachali, Reza T1 - On the origin of embrittlement in Mn containing and Zn-coated steels N2 - Grain boundary embrittlement in medium-Mn steels and liquid metal embrittlement (LME) in Zn-coated high strength steels are among key challenges on the way of safe application of sustainable steels for automotive industry. Using a novel density-based model for grain boundaries, we reveal that the affinity of a grain boundary to attract Mn and Zn atoms result in a segregation transition accompanied by interfacial structural changes. In case of the Zn, the simulations show that the amount of segregation abruptly increases with decreasing temperature, while the Zn content in the alloy, required for triggering the segregation transition, decreases. The results are discussed in the context of CALPHAD-integrated density-based grain boundary phase diagrams. T2 - DPG 2024 CY - Berlin, Germany DA - 17.03.2024 KW - Phase-Field Simulation KW - CALPHAD KW - Steels KW - Density-based Thermodynamics PY - 2024 AN - OPUS4-60743 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leo, Reinhold T1 - Duplex stainless steels - Compatibility for high-pressure hydrogen applications N2 - Duplex Stainless Steels (DSS) are an essential component used in the construction of transportation pipelines because of their many distinctive qualities. The choice of DSS for a particular hydrogen application mainly depends on its susceptibility level to Hydrogen Assisted Cracking (HAC). Several mechanisms have been proposed to describe the occurring microscale processes behind HAC, and these include metastable phase transformation, Hydrogen Enhanced Localized Plasticity (HELP), and Hydrogen Enhanced Decohesion (HEDE). This contribution describes the path to ascertain if DSS is suitable for high-pressure gaseous hydrogen applications. The interplay between several critical factors that result in HAC was examined using high-pressure gaseous hydrogen charging, Electron Backscatter Diffraction (EBSD), tensile testing and hydrogen concentration measurements using Carrier Gas Hot Extraction (CGHE). T2 - Third German-African Green Hydrogen Forum 2025 CY - Bernburg (Saale), Germany DA - 23.09.2025 KW - Hydrogen Assisted Cracking KW - High Pressure Hydrogen KW - Duplex Stainless Steels KW - Hollow Specimen Technique PY - 2025 AN - OPUS4-64302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kianinejad, Kaveh A1 - Fedelich, Bernard A1 - Darvishi Kamachali, Reza A1 - Schriever, Sina A1 - Manzoni, Anna Maria A1 - Agudo Jácome, Leonardo A1 - Megahed, Sandra A1 - Kamrani, Sepideh A1 - Saliwan Neumann, Romeo T1 - Experimentally informed multiscale creep modelling of additive manufactured Ni-based superalloys N2 - Excellent creep resistance at elevated temperatures, i.e. T / T_m> 0.5, due to γ-γ’ microstructure is one of the main properties of nickel-based superalloys. Due to its great importance for industrial applications, a remarkable amount of research has been devoted to understanding the underlying deformation mechanism in a wide spectrum of temperature and loading conditions. Additive manufactured (AM) nickel-based superalloys while being governed by similar γ-γ’ microstructure, exhibit AM-process specific microstructural characteristics, such as columnar grains, strong crystallographic texture (typically <001> fiber texture parallel to build direction) and compositional inhomogeneity, which in turn leads to anisotropic creep response in both stationary and tertiary phases. Despite the deep insights achieved recently on the correlation between process parameters and the resulting microstructure, the anisotropic creep behavior and corresponding deformation mechanism of these materials are insufficiently understood so far. One reason for this is the lack of capable material models that can link the microstructure to the mechanical behavior. To overcome this challenge, a multiscale microstructure-based approach has been applied by coupling crystal plasticity (CP) and polycrystal model which enables the inclusion of different deformation mechanisms and microstructural characteristics such as crystallographic texture and grain morphology. The method has been applied to experimental data for AM-manufactured INCONEL-738LC (IN738). The effect of different slip systems, texture, and morphology on creep anisotropy at 850°C has been investigated. Results suggest a strong correlation between superlattice extrinsic stacking fault (SESF) and microtwinning and observed creep anisotropy. T2 - EUROMAT 23 CY - Frankfurt a. M., Germany DA - 04.09.2023 KW - IN738LC KW - Creep anisotropy KW - Crystal plasticity PY - 2023 AN - OPUS4-58263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koerdt, Andrea T1 - The impact and potential of halophilic microorganisms on alternative fuels N2 - As more industrial interests focusing on using salt caverns and repurposed gas or petroleum reservoirs for alternative fuel storage, i.e. CO2/H2, the question raises whether microorganisms may impact the infrastructure, gas purity and storage condition over time. Environments with high salinity (> 1.5 Meq of NaCl) are resided by halophiles (salt-loving microorganisms). To compensate for the intensive osmotic stress, they have resorted to two main adaptation strategies: 1) production of compatible solutes and 2) accumulation of intracellular KCl. Microbial community analysis of several high salinity environments revealed a number of recurring genera, including Halomonas and Halanaerobium. However, the impact of halophiles on the overall integrity and stability of the storage facilities remain largely unknown. To evaluate the suitability and stability of saline storage facilities, several model halophilic microorganisms, such as members of Halomonas, will be selected as testing subjects. First, the impact of halophiles on the infrastructure will be determined using an integrative approach by combining a number of techniques, including electrochemistry, TOF-SIMS, SEM/FIB/EDS and FIB-TEM. Second, the abilities of halophiles to alter the fuel composition (i.e. increase/decrease the fractions of H2) will be monitored using gas chromatography by growing them under high pressure. As a result of climate change and the accompanying mandatory shift to renewable energy resources, microorganisms will continue to play an important role in the energy sector, both to their benefit and detriment. Thus, it is important to achieve a certain level of understanding regarding the activities and mechanisms of halophiles prior to large-scaled excursions. T2 - ISMOS-8 CY - Online meeting DA - 07.06.2021 KW - Microbiologically influenced corrosion KW - Hydrogen KW - Gas storage KW - Contamination PY - 2021 AN - OPUS4-52891 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - de Camargo, Andrea A1 - Arai, Marylyn Setsuko T1 - Upconversion nanoparticles for chemical, physical and biological sensing: from functionalization to point-of-care devices N2 - Among several applications, versatile upconversion nanoparticles (UCNPs) which can convert lower-energy infrared radiation into higher-energy visible or ultraviolet light, have emerged as one of the most powerful tools in the field of chemical, physical and biological sensing. The use of UCNPs in fluorescent sensors allows non-invasive, highly sensitive, and selective detection methods, which are particularly beneficial in environments requiring minimal interference and high precision for analytes that can range from metal ions to biomolecules. In this lecture, an overview and the state of the art will be given, accompanied by examples of our recent contributions to key areas such as chronic disease diagnostics, bacterial sensing, and multifunctionally responsive nanoplatforms: (1) An Enhanced Luminescence Lateral-Flow Assay (ELLA) designed for rapid (< 15 min) and early detection of acute kidney injury biomarkers in urine samples, using a commercial cell phone camera, will be presented. The platform is based on Er³⁺- and Tm³⁺-doped UCNPs whose emissions intensities are 40-fold enhanced by an Au-coated mesoporous silica shell, enabling the accurate detection of KIM-1 and NGAL biomarkers with detection limits as low as 0.23 ng/mL; (2) Also, a multifunctional nanoplatform that combines Tm³⁺-doped UCNPs with a Cu(I) complex for applications in oxygen sensing, optical thermometry, and emission colour tuning will be presented. The platform utilizes Luminescent Resonance Energy Transfer (LRET) to achieve efficient energy transfer, enabling red emission from the Cu(I) complex while allowing the use of the UCNP’s original emissions for thermometry. The dual functionality allows sensitive O2 detection and temperature measurements, with relative sensitivities of up to 1% K⁻¹; (3) The critical challenge of rapid bacterial detection and differentiation was addressed by the development of a novel UCNP-based sensor. By functionalizing UCNPs with the antibiotics - vancomycin for Gram-(+) and polymyxin-B for Gram-(-), and using Au nanoparticles as intensity quenchers, the sensor leverages a ratiometric "turn-on" mechanism for selective detection of the bacteria, through changes in the green/red (G/R) ratio for Er-UCNP@PEG4-Van, and blue/red (B/R) ratio for Tm-UCNP@PEG4-Poly. By this approach, differentiation was possible over a wide concentration range of bacteria (0.05 to 5 x 105 CFU/mL) with high correlation with actual bacterial counts (r = 0.99 for S. aureus, r = 0.91 for E. coli); (4) Recently, we have demonstrated a water dispersable ratiometric pH-nanosensor based on host-guest interaction of Tm3+/Yb3+ co-doped UCNPs functionalized with b-cyclodextrin (b-CD) and a pH-responsive nitrobenzoxadiazol dye modified with adamantane (NBD-Ad). The sensor shows a ratiometric emission response (blue/red) over a pH range of 8.0 – 11.0 with high reproducibility, excellent reusability and selectivity, even in the presence of interferents. Together, the presented examples highlight the versatility and potential of UCNPs to develop novel sensors, offering measurable advances in diagnostics, environmental monitoring, and beyond. T2 - Shift2025 - Spectral shaping for biomedical and energy applications CY - Tenerife, Spain DA - 13.10.2025 KW - Upconverting nanoparticles KW - Fluorescent sensors KW - Point-of-care devices PY - 2025 AN - OPUS4-65282 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - de Camargo, Andrea T1 - Enhanced emission of Nd3+ by localized silver nanocluster growth via direct laser writing in Ga-fluoride phosphate glasses N2 - Gallium fluoride phosphate glasses are promising materials for optical applications in the visible to near infrared spectra due to their wide transmission window and ability to accommodate optically active dopants. In this study, melt quenched glasses in the compositional system 25Ga(PO₃)₃–20ZnF₂–30BaF₂–(25–x–y)SrF₂–xAgNO₃–yNdF₃ (x = 0 -10 mol%, y = 0 or 1 mol%) were studied and fully characterized by conventional and spectroscopic techniques to understand the interaction of silver species and Nd³⁺ ions. In Ag+ doped samples, the observation of a broad emission band in the visible spectrum evidences the overlapping presence of Ag⁺, Ag nanoclusters (NCs), and [Ag₂]²⁺ species. In the sample doped with 10 mol% Ag⁺, the development of a dark yellow color and alterations in the emission profile suggest the formation of Ag nanoparticles. In an attempt to control and increase the formation of Ag nanoclusters in a localized way, the glasses with 3 and 5 mol% Ag+ were subjected to direct laser writing (DLW) with femtosecond laser pulses at variable inscription intensities and scan speeds. As expected, the approach led to localized growth of Ag-NCs with precise spatial control and as a consequence, the Nd³⁺ emissions in the NIR region (e.g. at1060 nm) were significantly enhanced in laser-structured regions as compared to unmodified areas, evidencing efficient energy transfer from silver species to Nd³⁺ ions. These results demonstrate that DLW, applied for the first time in these glasses, enables precise spatial control over silver nanocluster formation, offering a viable route to process optical glasses for photonic applications. T2 - XXIII - B-MRS Meeting CY - Salvador, Brazil DA - 28.09.2025 KW - Fluoride phosphate glasses KW - Direct laser writting KW - Neodymium KW - Silver nanoclusters PY - 2025 AN - OPUS4-65281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Pauw, Brian Richard A1 - Smales, Glen Jacob A1 - Anker, A. S. A1 - Balazs, D. M. A1 - Beyer, F. L. A1 - Bienert, Ralf A1 - Bouwman, W. G. A1 - Breßler, Ingo A1 - Breternitz, J. A1 - Brok, E. S. A1 - Bryant, G. A1 - Clulow, A. J. A1 - Crater, E. R. A1 - De Geuser, F. A1 - Giudice, A. D. A1 - Deumer, J. A1 - Disch, S. A1 - Dutt, S. A1 - Frank, K. A1 - Fratini, E. A1 - Gilbert, E. P. A1 - Hahn, Marc Benjamin A1 - Hallett, J. A1 - Hohenschutz, Max A1 - Hollamby, M. J. A1 - Huband, S. A1 - Ilavsky, J. A1 - Jochum, J. K. A1 - Juelsholt, M. A1 - Mansel, B. W. A1 - Penttilä, P. A1 - Pittkowski, R. K. A1 - Portale, G. A1 - Pozzo, L. D. A1 - Ricardo de Abreu Furtado Garcia, P. A1 - Rochels, L. A1 - Rosalie, Julian A1 - Saloga, P. E. J. A1 - Seibt, S. A1 - Smith, A. J. A1 - Smith, G. N. A1 - Annadurai, V. A1 - Spiering, G. A. A1 - Stawski, Tomasz A1 - Taché, O. A1 - Thünemann, Andreas A1 - Toth, K. A1 - Whitten, A. E. A1 - Wuttke, J. T1 - The human factor - Results of a small-angle scattering data analysis round robin N2 - A Round Robin study has been carried out to estimate the impact of the human element in small-angle scattering data analysis. Four corrected datasets were provided to participants ready for analysis. All datasets were measured on samples containing spherical scatterers, with two datasets in dilute dispersions, and two from powders. Most of the 46 participants correctly identified the number of populations in the dilute dispersions, with half of the population mean entries within 1.5 % and half of the population width entries within 40 %, respectively. Due to the added complexity of the structure factor, much fewer people submitted answers on the powder datasets. For those that did, half of the entries for the means and widths were within 44 % and 86 % respectively. This Round Robin experiment highlights several causes for the discrepancies, for which solutions are proposed. KW - Round robin KW - Sall-angle scattering KW - Nanostructure quantification KW - Nanostructure KW - SAXS KW - MOUSE KW - X-ray scattering KW - Size distribution KW - Nanoparticles PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571342 DO - https://doi.org/10.48550/arXiv.2303.03772 SP - 1 EP - 23 PB - Cornell University CY - Ithaca, NY AN - OPUS4-57134 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -