TY - CONF A1 - Bhadeliya, Ashok T1 - High Temperature Fatigue Crack Growth in Nickel-Based Alloys Refurbished by Additive Manufacturing and Brazing N2 - Hybrid additive manufacturing plays a crucial role in the restoration of gas turbine blades, where e.g., the damaged blade tip is reconstructed by the additive manufacturing process on the existing blade made of a parent nickel-based alloy. However, inherent process-related defects in additively manufactured material, along with the interface created between the additively manufactured and the cast base material, impact the fatigue crack growth behavior in bi-material components. This study investigates the fatigue crack growth behavior in bi-material specimens of nickel-based alloys, specifically, additively manufactured STAL15 and cast alloy 247DS. The tests were conducted at 950 °C with stress ratios of 0.1 and -1. Metallographic and fractographic investigations were carried out to understand crack growth mechanisms. The results revealed significant retardation in crack growth at the interface. This study highlights the potential contributions of residual stresses and microstructural differences to the observed crack growth retardation phenomenon, along with the conclusion from an earlier study on the effect of yield strength mismatch on crack growth behavior at a perpendicular interface in bi-material specimens. T2 - Superalloys 2024 Conference CY - Champion, PA, USA DA - 08.09.2024 KW - Fatigue crack growth KW - Bi-material structure KW - Nickel-based alloys KW - Additive Manufacturing KW - Brazing PY - 2024 AN - OPUS4-61047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - How 3D X-ray Imaging and Residual Stress Analysis contribute to safety of materials and structures N2 - The safety of materials and structures can be detrimentally influenced by residual stresses (RS) and defect populations (voids or other features leading to failure) if they are not correctly accounted for in the design. Therefore, the accurate characterization of these features and the consideration of their impact is crucial for the safe design of components. The ability to characterize these features non-destructively enables the direct correlation on resulting mechanical performance. 3D X-ray computed tomography (XCT) is used to resolve and quantitively analyze microstructural features (i.e., voids, porosity). This is often used to assess the capability of the manufacturing route, i.e., additive manufacturing (AM). The non-destructive nature of the method also enables the study of the evolution of damage in materials from such microstructural features [1]. Using in-situ methods such as compression or tension, the propagation of damage from initial microstructure can be assessed, aiding our understanding of which features are detrimental to safety [3]. Diffraction based residual stress analysis methods including high energy X-ray and neutron diffraction can be used to study the residual stress gradients from the surface, subsurface and into the bulk non-destructively. These methods can be used to study the influence of heat treatments on residual stress and can be combined with XCT results to correlate the interaction of residual stresses with microstructural features (i.e., void clusters). This talk will give an overview of the capabilities and opportunities of 3D XCT and diffraction based residual stress analysis to close the gap in our understanding of material degradation on mechanical performance, enabling manufacturers to adjust their designs accordingly for safety critical applications. A particular focus will be made on examples where the two advanced techniques are combined to enhance such understanding. T2 - MaterialsWeek 2025 CY - Frankfurt am Main, Germany DA - 02.04.2025 KW - Neutron Diffraction KW - Residual Stress KW - X-ray Computed Tomography KW - Additive Manufacturing KW - Large Scale facilites KW - Creep KW - Defects KW - BAMline PY - 2025 AN - OPUS4-62895 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Jakob T1 - Neutron Diffraction Based Residual Stress Analysis of Additively Manufactured Alloys N2 - Additive manufacturing methods such as laser powder bed fusion offer an enormous flexibility in the efficient design of parts. In this process, a laser locally melts feedstock powder to build up a part layer-by-layer. It is this localized processing manner imposing large temperature gradients, resulting in the formation of internal stress and characteristic microstructures. Produced parts inherently contain high levels of residual stress accompanied by columnar grain growth and crystallographic texture. On a smaller scale, the microstructure is characterized by competitive cell-like solidification with micro segregation and dislocation entanglement. In this context, it is crucial to understand the interplay between microstructure, texture, and residual stress to take full advantage of the freedom in design. In fact, X-ray and neutron diffraction are considered as the benchmark for the non-destructive characterization of surface and bulk residual stress. The latter, characterized by a high penetration power in most engineering alloys, allows the use of diffraction angle close to 90°, enabling the employment of a nearly cubic gauge volume. However, the complex hierarchical microstructures produced by additive manufacturing present significant challenges towards the reliable characterization of residual stress by neutron diffraction. Since residual stress is not the direct quantity being measured, the peak shift imposed by the residual stress present in a material must be converted into a macroscopic stress. First, an appropriate lattice plane must be selected that is easily accessible (i.e., high multiplicity) and insensitive to micro strain accumulation. Second, a stress-free reference must be known to calculate a lattice strain, which can be difficult to define for the heterogeneous microstructures produced by additive manufacturing. Third, an appropriate set of diffraction elastic constants that relate the lattice strain to the macroscopic stress must be known. In this presentation, advancements in the field of residual stress analysis using neutron diffraction are presented on the example of the Ni-based superalloy Inconel 718. The effect of the complex microstructure on the determination of residual stress by neutron diffraction is presented. It is shown, how to deal with the determination of the stress-free reference. It is also shown that the selection of an appropriate set of diffraction elastic constants depends on the microstructure. Finally, the role of the crystallographic texture in the determination of the residual stress is shown. T2 - Deutsche Neutronenstreutagung CY - Aachen, Germany DA - 16.09.2024 KW - Additive Manufacturing KW - Neutron Diffraction KW - Electron Backscatter Diffraction KW - Laser Powder Bed Fusion PY - 2024 AN - OPUS4-61476 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ulbricht, Alexander T1 - Evolution of Creep Damage of 316L Produced by Laser Powder Bed Fusion N2 - The damage mechanisms of metallic components produced by process laser powder bed fusion differ significantly from those typically observed in conventionally manufactured variants of the same alloy. This is due to the unique microstructures of additively manufactured materials. Herein, the focus is on the study of the evolution of creep damage in stainless steel 316L specimens produced by laser powder bed fusion. X-ray computed tomography is used to unravel the influence of the process-specific microstructure from the influence of the initial void distribution on creep damage mechanisms. The void distribution of two specimens tested at 600 °C and 650 °C is analyzed before a creep test, after an interruption, and after fracture. The results indicate that the formation of damage is not connected to the initial void distribution. Instead, damage accumulation at grain boundaries resulting from intergranular cracking is observed. T2 - Annual International Solid Freeform Fabrication Symposium CY - Austin, TX, USA DA - 14.08.2023 KW - AISI 316L KW - Additive Manufacturing KW - Computed Tomography KW - Creep KW - Laser Powder Bed Fusion KW - Microstructure KW - PBF-LB/M/316L PY - 2023 AN - OPUS4-58285 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ulbricht, Alexander T1 - Formation of Creep Damage of 316L Produced by Laser Powder Bed Fusion N2 - The damage mechanisms of metallic components produced by process laser powder bed fusion differ significantly from those typically observed in conventionally manufactured variants of the same alloy. This is due to the unique microstructures of additively manufactured materials. Herein, the focus is on the study of the evolution of creep damage in stainless steel 316L specimens produced by laser powder bed fusion. X-ray computed tomography is used to unravel the influence of the process-specific microstructure from the influence of the initial void distribution on creep damage mechanisms. The void distribution of two specimens tested at 600 °C and 650 °C is analyzed before a creep test, after an interruption, and after fracture. The results indicate that the formation of damage is not connected to the initial void distribution. Instead, damage accumulation at grain boundaries resulting from intergranular cracking is observed. T2 - 4th Symposium on Materials and Additive Manufacturing - Additive 2024 CY - Berlin, Germany DA - 12.06.2024 KW - AISI 316L KW - Additive Manufacturing KW - Computed Tomography KW - Creep KW - Laser Powder Bed Fusion KW - Microstructure KW - PBF-LB/M/316L PY - 2024 AN - OPUS4-60295 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Jakob T1 - Diffraction and Single-Crystal Elastic Constants of Laser Powder Bed Fused Inconel 718 N2 - Laser powder bed fusion (PBF-LB/M) of metallic alloys is a layer-wise additive manufacturing process that provides significant scope for more efficient designs of components, benefiting performance and weight, leading to efficiency improvements for various sectors of industry. However, to benefit from these design freedoms, knowledge of the high produced induced residual stress and mechanical property anisotropy associated with the unique microstructures is critical. X-ray and neutron diffraction are considered the benchmark for non-destructive characterization of surface and bulk internal residual stress. The latter, characterized by the high penetration power in most engineering alloys, allows for the use of a diffraction angle close to 90° enabling a near cubic sampling volume to be specified. However, the complex microstructures of columnar growth with inherent crystallographic texture typically produced during PBF-LB/M of metallics present significant challenges to the assumptions typically required for time efficient determination of residual stress. These challenges include the selection of an appropriate set of diffraction elastic constants and a representative lattice plane suitable for residual stress analysis. In this contribution, the selection of a suitable lattice plane family for residual stress analysis is explored. Furthermore, the determination of an appropriate set of diffraction and single-crystal elastic constants depending on the underlying microstructure is addressed. In-situ loading experiments have been performed at the Swiss Spallation Neutron Source with the main scope to study the deformation behaviour of laser powder bed fused Inconel 718. Cylindrical tensile bars have been subjected to an increasing mechanical load. At pre-defined steps, neutron diffraction data has been collected. After reaching the yield limit, unloads have been performed to study the accumulation of intergranular strain among various lattice plane families. T2 - 11th European Conference on Residual Stresses CY - Prag, Czech Republic DA - 03.06.2024 KW - Additive Manufacturing KW - Laser Powder Bed fusion KW - Diffraction Elastic Constants KW - Microstructure KW - Electron Backscatter Diffraction PY - 2024 AN - OPUS4-60289 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Jakob T1 - Diffraction and Single-Crystal Elastic Constants of Laser Powder Bed Fused Inconel 718 N2 - In this presentation, the results of the determination of the diffraction and single-crystal elastic constants of laser powder bed fused Inconel 718 are presented. The analysis is based on high-energy synchrotron diffraction experiments performed at the Deutsches Elektronen-Synchrotron. It is shown that the characteristic microstructure of laser powder bed fused Inconel 718 impacts the elastic anisotropy and therefore the diffraction and single-crystal elastic constants. Finally, the consequences on the diffraction-based residual stress determination of laser powder bed fused Inconel 718 are discussed. T2 - AWT-Fachausschuss 13 "Eigenspannungen" CY - Wolfsburg, Germany DA - 19.03.2024 KW - Additive Manufacturing KW - Laser Powder Bed fusion KW - Diffraction KW - In-Situ Testing KW - Diffraction Elastic Constants PY - 2024 AN - OPUS4-59900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Jakob T1 - Influence of Microstructure on the Diffraction-Based Residual Stress Determination in Laser Powder Bed Fused Inconel 718 N2 - Additive manufacturing processes such as laser powder bed fusion (PBF-LB) offer the ability to produce parts in a single manufacturing step. On the one hand, this manufacturing technique offers immense geometric freedom in part design due to its layer-by-layer manufacturing strategy. On the other hand, the localized melting and solidification impose the presence of large temperature gradients in the process. From a microstructural perspective, this inevitably results in micro-segregation and a columnar grain structure, often paired with a significant crystallographic texture. Even worse, these large temperature gradients can lead to internal stress-induced deformation or cracking during processing. At the very least, residual stress is retained in the final structures as a footprint of this internal stress. In this context, diffraction-based methods allow the non-destructive characterization of the residual stress field in a non-destructive fashion. However, the accuracy of these methods is directly related to the microstructural characteristics of the material of interest. First, diffraction-based methods access microscopic lattice strains. To relate these lattice strains to a macroscopic stress, so-called diffraction elastic constants must be known. The deformation behavior is directly linked to the microstructure. Therefore, the diffraction elastic constants also depend on the microstructure. Second, the presence of crystallographic texture should be considered in the residual stress determination, as variations in crystal orientations contribute differently to the diffraction signal. Here we present the influence of the microstructure on the determination of residual stress by diffraction-based methods in as-built PBF-LB Inconel 718 parts. We obtained different microstructures by employing two different scanning strategies. In particular, different crystallographic textures were obtained by changing the relative angle of the scan vectors to the geometric axes of the part. The texture-based characterization of the residual stress field was carried out by surface, sub-surface, and bulk residual stress measurements. It was found that the residual stress determination significantly depends on the microstructure for strong crystallographic textures. T2 - Material Science and Engineering Congress CY - Darmstadt, Germany DA - 24.09.2024 KW - Additive Manufacturing KW - Electron Backscatter Diffraction KW - Microstructure KW - Residual Stress KW - X-ray Diffraction PY - 2024 AN - OPUS4-61475 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Capabilities at BAM, division 8.5- X-ray Imaging N2 - The X-ray computed tomography capabilities at BAM (especially in Division 8.5) are shown. It is also shown that the group possesses X-ray refraction radiography techniques, which are complementary to absorption radiography, and uses diffraction for residual stress analysis. Examples of applications in the field of Additive Manufacturing ale also shown. T2 - DGM AK XCT CY - Berlin, Germany DA - 27.11.2024 KW - X-ray Computed tomography KW - Defects KW - X-ray refraction radiography KW - Additive Manufacturing PY - 2024 AN - OPUS4-62046 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni A1 - Fritsch, Tobias A1 - Schröder, Jakob A1 - Mishurova, Tatiana A1 - Ulbricht, Alexander A1 - Evans, Alexander A1 - Serrano-Munoz, Itziar T1 - How to experimentally determine residual stress in AM structures N2 - The experimental determination of residual stress becomes more complicated with increasing complexity of the structures investigated. Unlike the conventional and most of the additive manufacturing (AM) fabrication techniques, laser powder bed fusion (PBF-LB) allows the production of complex structures without any additional manufacturing step. However, due to the extremely localized melting and solidification, internal stress-induced deformation and cracks are often observed. In the best case, significant residual stress is retained in the final structures as a footprint of the internal stress during manufacturing. Here we report solutions to the most prevalent challenges when dealing with the diffraction-based determination of residual stress in AM structures, in particular the choice of the correct diffraction elastic constants. We show that for Nickel-based alloys, the diffraction elastic constants of AM material significantly deviate from their conventional counterparts. Furthermore, measurement strategies to overcome the hurdles appearing when applying diffraction-based techniques to complex-shaped lattice structures are presented: a) proper sample alignment within the beam, b) the proper determination of the residual stress field in a representative part of the structure (i.e., with an engineering meaning). Beyond the principal stress magnitude, the principal direcions of residual stress are discussed for different geometries and scan strategies, as they are relevent for failure criteria. We show that the RS in the lattice struts can be considered to be uniaxial and to follow the orientation of the strut, while the RS in the lattice knots is more hydrostatic. Additionally, we show that strain measurements in at least seven independent directions are necessary for the correct estimation of the principal stress directions. The measurement directions should be chosen according to the sample geometry and to an informed choice on the possible strain field (i.e., reflecting the scan strategy). We finally show that if the most prominent direction is not measured, the error in the calculated stress magnitude increases in such a manner that no reliable assessment of RS state can be made. T2 - Additive 2024 CY - Berlin, Germany DA - 12.06.2024 KW - Neutron Diffraction KW - Residual Stress KW - X-ray Computed Tomography KW - Additive Manufacturing KW - Lattice Structure KW - Inconel PY - 2024 AN - OPUS4-60423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis T1 - Creep Behavior of Stainless Steel 316L Manufactured by Laser Powder Bed Fusion N2 - Metal additive manufacturing (Metal AM) continues to gain momentum. Many companies explore the manufacturing of innovative products, including components for safety critical applications. Despite the intensive research of recent years, a fundamental understanding of the process‑structure‑property relationships remains challenging due to, i.a., the inherently complex and highly hierarchical microstructures arising from the wide range of build process parameter variability. This contribution presents the resu lts of an experimental study on the creep behavior of an austenitic 316L stainless steel produced by laser powder bed fusion (PBF LB/M/316L) with an emphasis on understanding the effects of microstructure on creep mechanisms. Hot tensile tests and constant force creep tests at 600 °C and 650 °C, X ray computed tomography, as well as optical and electron microscopy were performed. The produced PBF LB/M/316L exhibits a low void population 0.01 %) resulting from the manufacturing parameters used and which a llowed us to understand the effects of other microstructural aspects on creep behavior, e.g., grain morphology and dislocation substructure. A hot‑rolled variant of 316L hwas also tested as a reference. The produced PBF LB/M/316L possesses shorter primary and secondary creep stages and times to rupture and smaller creep stress exponents than the hot‑rolled variant. Overall, the creep damage is more extensive in the PBF LB/M/316L and is characterized as predominantly intergranular. It is considered that the damage behavior is mainly impacted by the formation of precipitates at the grain boundaries combined with their unfavorable orientation. The dislocation substructure and local elemental segregation appear to have a decisive impact on the overall creep behavior. T2 - 16th International Conference on Creep and Fracture of Engineering Materials and Structures CY - Bangalore, India DA - 28.07.2024 KW - AGIL KW - 316L KW - Additive Manufacturing KW - Creep KW - Microstructure evolution PY - 2024 AN - OPUS4-60839 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zocca, Andrea A1 - Günster, Jens T1 - Towards a debinding-free additive manufacturing of ceramics: A development perspective of water-based LSD and LIS technologies N2 - Ceramic additive manufacturing (AM) requires a complex process chain with various post-processing steps that require expensive machines and special expertise. The key to further market penetration is AM that makes it possible to integrate into an already established ceramic process chain. Most successful AM technologies for ceramics are, however, based on processes that initially have been developed for polymeric materials. For ceramics AM, polymers or precursors are loaded with ceramic particles. This strategy facilitates the entry into AM, however the introduction of organic additives into the ceramic process chain represents a considerable technological challenge to ultimately obtain a ceramic component after additive shaping. In the present communication, two technologies based on ceramic suspensions will be introduced, the “layerwise slurry deposition” (LSD) and “laser induced slip casting” (LIS) technology. Both technologies take advantage of the high packing densities reached by conventional slip casting and moreover enable the processing of fines, even nanoparticles. KW - Additive Manufacturing KW - Ceramic KW - Water-based KW - Debinding KW - Slurry PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605531 DO - https://doi.org/10.1016/j.oceram.2024.100632 SN - 2666-5395 VL - 19 SP - 1 EP - 13 PB - Elsevier B.V. AN - OPUS4-60553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Knabe, C. A1 - Stiller, M. A1 - Kampschulte, M. A1 - Wilbig, Janka A1 - Peleska, B. A1 - Günster, Jens A1 - Gildenhaar, R. A1 - Berger, G. A1 - Rack, A. A1 - Linow, U. A1 - Heiland, M. A1 - Rendenbach, C. A1 - Koerdt, S. A1 - Steffen, C. A1 - Houshmand, A. A1 - Xiang-Tischhauser, L. A1 - Adel-Khattab, D. T1 - A tissue engineered 3D printed calcium alkali phosphate bioceramic bone graft enables vascularization and regeneration of critical-size discontinuity bony defects in vivo N2 - Recently, efforts towards the development of patient-specific 3D printed scaffolds for bone tissue engineering from bioactive ceramics have continuously intensified. For reconstruction of segmental defects after subtotal mandibulectomy a suitable tissue engineered bioceramic bone graft needs to be endowed with homogenously distributed osteoblasts in order to mimic the advantageous features of vascularized autologous fibula grafts, which represent the standard of care, contain osteogenic cells and are transplanted with the respective blood vessel. Consequently, inducing vascularization early on is pivotal for bone tissue engineering. The current study explored an advanced bone tissue engineering approach combining an advanced 3D printing technique for bioactive resorbable ceramic scaffolds with a perfusion cell culture technique for pre-colonization with mesenchymal stem cells, and with an intrinsic angiogenesis technique for regenerating critical size, segmental discontinuity defects in vivo applying a rat model. To this end, the effect of differing Si-CAOP (silica containing calcium alkali orthophosphate) scaffold microarchitecture arising from 3D powder bed printing (RP) or the Schwarzwalder Somers (SSM) replica fabrication technique on vascularization and bone regeneration was analyzed in vivo. In 80 rats 6-mm segmental discontinuity defects were created in the left femur. KW - Additive Manufacturing KW - Bio active ceramic KW - In-vivo KW - Alcium alkali phosphate PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584555 DO - https://doi.org/10.3389/fbioe.2023.1221314 SN - 2296-4185 VL - 11 SP - 1 EP - 20 PB - Frontiers SA CY - Lausanne AN - OPUS4-58455 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günster, Jens T1 - Binder Jetting of Advanced Ceramics N2 - The Binder Jetting BJ process is one of the most versatile additive manufacturing technologies in use. In this process a binder is locally jetted into a powder bed for the consolidation of a 3D structure, layer by layer. Basically, all materials which can be provided as a flowable powder and, thus, spreadable to a thin layer, can be processed. Metals, ceramics and polymers are processable, but also materials from nature, such as sand, wood sawdust and insect frass. Moreover, the BJ technology is adapted to large building volumes of some cubic meters easily. Besides these striking advantages, the manufacture of ceramic parts by BJ is still challenging, as the packing density of the powder bed is generally too low and the particle size of a flowable powder too large for a successful densification of printed parts in a subsequent sintering step to an advanced ceramic product. After an introduction of binder jetting in general and highlighting some examples, strategies for obtaining dense ceramic parts by BJ will be introduced. T2 - yCAM 2022 CY - Barcelona, Spain DA - 08.11.2022 KW - Additive Manufacturing KW - Ceramics PY - 2022 AN - OPUS4-59887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Diener, S. A1 - Schubert, Hendrik A1 - Held, A. A1 - Katsikis, N. A1 - Günster, Jens A1 - Zocca, Andrea T1 - Influence of the dispersant on the parts quality in slurry-based binder jetting of SiC ceramics N2 - Binder jetting is establishing more and more in the ceramic industry to produce large complex shaped parts. A parameter with a great impact on the quality of the parts is the binder–powder interaction. The use of ceramic slurries as feedstock for this process, such as in the layerwise slurry deposition–print technology, allows a great flexibility in the composition. Such slurries are typically composed of ceramic powder, water, and small amounts of various additives. The understanding of the effect of these components on the printing quality is thus essential for the feedstock development. Four models were developed regarding the impact of additives, such as dispersants on printing. These models were confirmed or rebutted by experiments performed for an SiC slurry system with two different concentrations of a dispersant and a commercial phenolic resin used as a binder. It is shown that for this system the influence of the dispersant on the curing behavior and the clogging of the pores by dispersant can be neglected. The redispersion of the dispersant after the curing of the resin has no or only a minor effect. However, the wetting behavior determined by the surface energies of the system seem to be most crucial. In case the surface energy of the slurry additive is significantly lower than the surface energy of the binder, the strength of the green parts and the printing quality will be low. This was shown by inverse gas chromatography, contact angle measurement, rheological characterization, and mechanical tests with casted samples. KW - Additive Manufacturing KW - Binder Jetting KW - Layerwise slurry deposition KW - Silicon carbide KW - Wetting PY - 2022 DO - https://doi.org/10.1111/jace.18693 SN - 1551-2916 VL - 2022 SP - 1 EP - 15 PB - Wiley-Blackwell CY - Oxford AN - OPUS4-55542 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zocca, Andrea T1 - Combination of layerwise slurry deposition and binder jetting (lsd-print) for the additive manufacturing of advanced ceramic materials N2 - Powder bed technologies are amongst the most successful Additive Manufacturing (AM) techniques. Powder bed fusion and binder jetting especially are leading AM technologies for metals and polymers, thanks to their high productivity and scalability. The application of these techniques to most ceramics has been difficult so far, because of the challenges related to the deposition of homogeneous powder layers when using fine powders. In this context, the “layerwise slurry deposition” (LSD) has been developed as a layer deposition method which enables the use of powder bed AM technologies also for advanced ceramic materials. The layerwise slurry deposition consists of the layer-by-layer deposition of a ceramic slurry by means of a doctor blade, in which the slurry is deposited and dried to achieve a highly packed powder layer. This offers high flexibility in the ceramic feedstock used, especially concerning material and particle size. The LSD technology can be combined with binder jetting to develop the so-called “LSDprint” process for the additive manufacturing of ceramics. The LSDprint technology combines the high-speed printing of binder jetting with the possibility of producing a variety of high-quality ceramics with properties comparable to those achieved by traditional processing. In this presentation, the LSD process will be introduced and several examples of application ranging from silicate to high-performance ceramics will be shown. Recent developments towards the scale-up and industrialization of this process will be discussed, alongside future perspectives for the multi-material additive manufacturing. T2 - Shaping 8 CY - Dübendorf, Switzerland DA - 14.09.2022 KW - Additive Manufacturing KW - 3D printing KW - Ceramics PY - 2022 AN - OPUS4-56523 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Melo Bernardino, Raphael A1 - Valentino, S. A1 - Franchin, G. A1 - Günster, Jens A1 - Zocca, Andrea T1 - Manufacturing of ceramic components with internal channels by a novel additive/subtractive hybridizazion process N2 - A new approach for fabrication of ceramic components with inner channels is proposed, as a result of the combination of two additive and one subtractive manufacturing processes. In this project, porcelain parts are manufactured by the Layerwise Slurry Deposition (LSD) process, meanwhile end milling and Direct Ink Writing (DIW) are applied to create channels on the surface of the deposited ceramic. Unique to the LSD process is the Formation of a freestanding powder bed with a mechanical strength comparable to conventional slip casted ceramic green bodies. Combining these three processes allows the manufacturing of ceramic objects containing an internal path of ink, which in this case was a graphite-based ink that can be further eliminated by heat treatment to obtain a porcelain object embedded with channels. The results show the capabilities of this method and its potential to fabricate not only parts with inner channels, but also multi-material and multi-functional components (such as integrated electronic circuits). KW - Additive Manufacturing KW - Layerwise Slurry Deposition KW - Hybrid Manufacturing PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510012 UR - https://www.sciencedirect.com/science/article/pii/S2666539520300109?via%3Dihub DO - https://doi.org/10.1016/j.oceram.2020.100010 VL - 2 SP - 100010 PB - Elsevier Ltd. AN - OPUS4-51001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ginés-Palomares, Juan-Carlos A1 - Facchini, Leonardo A1 - Wilbig, Janka A1 - Zocca, Andrea A1 - Stoll, Enrico A1 - Günster, Jens T1 - Melt Pool Stability during Local Laser Melting of Lunar Regolith with Large Laser Spots and Varying Gravity N2 - In order to increase the sustainability of future lunar missions, techniques for in-situ resource utilization (ISRU) must be developed. In this context, the local melting of lunar dust (regolith) by laser radiation for the production of parts and larger structures was investigated in detail. With different experimental setups in normal and microgravity, laser spots with diameters from 5 mm to 100 mm were realized to melt the regolith simulant EAC-1A and an 80%/20% mixture of TUBS-T and TUBS-M, which are used as a substitute for the actual lunar soil. In the experiments performed, the critical parameters are the size of the laser spot, the velocity of the laser spot on the surface of the powder bed, the gravity and the wettability of the powder bed by the melt. The stability of the melt pool as a function of these parameters was investigated and it was found that the formation of a stable melt pool is determined by gravity for large melt pool sizes in the range of 50 mm and by surface tension for small melt pool sizes in the range of a few mm. KW - Additive Manufacturing KW - Regolith KW - Laser melting KW - ISRU PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639621 DO - https://doi.org/10.1016/j.amf.2025.200227 SN - 2950-4317 VL - 4 IS - 3 SP - 1 EP - 10 PB - Elsevier Ltd. AN - OPUS4-63962 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Diener, S. A1 - Zocca, Andrea A1 - Günster, Jens T1 - Literature review: Methods for achieving high powder bed densities in ceramic powder bed based additive manufacturing N2 - In additive manufacturing the powder bed based processes binder jetting and powder bed fusion are increasingly used also for the production of ceramics. Final part properties depend to a high percentage on the powder bed density. Therefore, the aim is to use the best combination of powder deposition method and powder which leads to a high packing of the particles. The influence of flowability, powder properties and deposition process on the powder bed density is discussed and the different deposition processes including slurry-based ones are reviewed. It turns out that powder bed density reached by slurry-based layer deposition exceeds conventional powder deposition, however, layer drying and depowdering are extra steps or more time-consuming for the slurry route. Depending on the material properties needed the most suitable process for the part has to be selected. KW - Additive Manufacturing KW - Powder-based processes KW - Powder bed density PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534992 DO - https://doi.org/10.1016/j.oceram.2021.100191 VL - 8 SP - 100191 PB - Elsevier Ltd. AN - OPUS4-53499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chi, J. A1 - Agea Blanco, B. A1 - Bruno, Giovanni A1 - Günster, Jens A1 - Zocca, Andrea T1 - Self-Organization Postprocess for Additive Manufacturingin Producing Advanced Functional Structure and Material N2 - Additive manufacturing (AM) is developing rapidly due to itsflexibility in producing complex geometries and tailored material compositions. However, AM processes are characterized by intrinsic limitations concerning their resolution and surface finish, which are related to the layer-by-layer stacking process. Herein, a self-organization process is promoted as an approach to improve surface quality and achieve optimization of 3D minimal surface lightweight structures. The self-organization is activated after the powder bed 3D printing process via local melting, thereby allowing surface tension-driven viscous flow.The surface roughness Ra (arithmetic average of the roughness profile) could bedecreased by a factor of 1000 and transparent lenses and complex gyroid structures could be produced for demonstration. The concept of self-organization is further elaborated by incorporating external magnetic fields to intentionally manipulate magnetic particles, which are mixed with the polymer before printing and self-organization. This concept can be applied to develop programmable materials with specific microtextures responding to the external physical conditions. KW - Additive Manufacturing KW - Self-organization KW - Triply Periodical Minimal Surface PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540588 DO - https://doi.org/10.1002/adem.202101262 VL - 24 IS - 6 SP - 1 EP - 8 PB - Wiley VCH AN - OPUS4-54058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -