TY - CONF A1 - Portella, Pedro Dolabella T1 - Materials testing - How to put the right question and get the right answers T2 - MSE 2010, Keynote lecture CY - Darmstadt, Germany DA - 2010-08-24 PY - 2010 AN - OPUS4-21953 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Portella, Pedro Dolabella T1 - Fiber reinforced titanium matrix composites: production, mechanical testing and damage characterization T2 - Materials Science & Technology 2007 Conference & Exhibition CY - Detroit, MI, USA DA - 2007-09-16 PY - 2007 AN - OPUS4-14959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Portella, Pedro Dolabella T1 - High temperature fatigue of nickel-base superalloys single crystals T2 - Materials Science & Technology 2007 Conference & Exhibition CY - Detroit, MI, USA DA - 2007-09-16 PY - 2007 AN - OPUS4-14960 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Portella, Pedro Dolabella T1 - LCF and TMF behavior of a Ti-6242/SCS-6 titanium matrix composite T2 - Fatigue sous sollicitations thermiques, SF2M CY - Paris, France DA - 2007-05-23 PY - 2007 AN - OPUS4-14958 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bayerlein, Bernd A1 - Waitelonis, Jörg A1 - Birkholz, Henk A1 - Jung, Matthias A1 - Schilling, Markus A1 - v. Hartrott, Philipp A1 - Bruns, Marian A1 - Schaarschmidt, Jörg A1 - Beilke, Kristian A1 - Mutz, Marcel A1 - Nebel, Vincent A1 - Königer, Veit A1 - Beran, Lisa A1 - Kraus, Tobias A1 - Vyas, Akhilesh A1 - Vogt, Lars A1 - Blum, Moritz A1 - Ell, Basil A1 - Chen, Ya‐Fan A1 - Waurischk, Tina A1 - Thomas, Akhil A1 - Durmaz, Ali Riza A1 - Ben Hassine, Sahar A1 - Fresemann, Carina A1 - Dziwis, Gordian A1 - Beygi Nasrabadi, Hossein A1 - Hanke, Thomas A1 - Telong, Melissa A1 - Pirskawetz, Stephan A1 - Kamal, Mohamed A1 - Bjarsch, Thomas A1 - Pähler, Ursula A1 - Hofmann, Peter A1 - Leemhuis, Mena A1 - Özçep, Özgür L. A1 - Meyer, Lars‐Peter A1 - Skrotzki, Birgit A1 - Neugebauer, Jörg A1 - Wenzel, Wolfgang A1 - Sack, Harald A1 - Eberl, Chris A1 - Portella, Pedro Dolabella A1 - Hickel, Tilmann A1 - Mädler, Lutz A1 - Gumbsch, Peter T1 - Concepts for a Semantically Accessible Materials Data Space: Overview over Specific Implementations in Materials Science N2 - This article describes advancements in the ongoing digital transformation in materials science and engineering. It is driven by domain‐specific successes and the development of specialized digital data spaces. There is an evident and increasing need for standardization across various subdomains to support science data exchange across entities. The MaterialDigital Initiative, funded by the German Federal Ministry of Education and Research, takes on a key role in this context, fostering collaborative efforts to establish a unified materials data space. The implementation of digital workflows and Semantic Web technologies, such as ontologies and knowledge graphs, facilitates the semantic integration of heterogeneous data and tools at multiple scales. Central to this effort is the prototyping of a knowledge graph that employs application ontologies tailored to specific data domains, thereby enhancing semantic interoperability. The collaborative approach of the Initiative's community provides significant support infrastructure for understanding and implementing standardized data structures, enhancing the efficiency of data‐driven processes in materials development and discovery. Insights and methodologies developed via the MaterialDigital Initiative emphasize the transformative potential of ontology‐based approaches in materials science, paving the way toward simplified integration into a unified, consolidated data space of high value. KW - Semantic Interoperability KW - Data Spaces KW - Integration Workflows KW - MaterialDigital PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622952 DO - https://doi.org/10.1002/adem.202401092 SN - 1527-2648 SP - 1 EP - 25 PB - Wiley-VCH CY - Weinheim AN - OPUS4-62295 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fedelich, Bernard A1 - Epishin, A. A1 - Link, T. A1 - Klingelhöffer, Hellmuth A1 - Künecke, Georgia A1 - Portella, Pedro Dolabella T1 - Experimental characterization and mechanical modeling of creep induced rafting in superalloys N2 - A constitutive model has been developed for the high temperature mechanical behavior of single crystal superalloys, including rafting and its consequences. The flow stress depends on the γ channel width via the Orowan stress. An evolution equation for channel widening during high temperature straining has been derived and calibrated with measurements. Therein, rafting is assumed to be driven by the relaxation of internal stresses. The model is able to represent the mechanical softening at high stresses consecutive to rafting. The model has been applied to simulate rafting during uniaxial creep in several crystal orientations, in notched specimens as well as in cyclically loaded specimens. KW - Single crystal KW - Superalloys KW - Rafting KW - Creep KW - Viscoplasticity KW - Constitutive law PY - 2012 DO - https://doi.org/10.1016/j.commatsci.2012.05.071 SN - 0927-0256 VL - 64 SP - 2 EP - 6 PB - Elsevier CY - Amsterdam AN - OPUS4-26401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epishin, Alexander A1 - Link, T. A1 - Klingelhöffer, Hellmuth A1 - Fedelich, Bernard A1 - Portella, Pedro Dolabella T1 - Creep damage of single-crystal nickel base superalloys: mechanisms and effect on low cycle fatigue N2 - The main mechanisms of creep damage of single-crystal nickel-base superalloys are the loss of the interface coherency, coarsening of the γ / γ'-microstructure, precipitation of topologically closed packed phases and growth of porosity. This degradation deteriorates the mechanical properties such as yield stress, creep lifetime and especially low-cycle fatigue life, which can be reduced nearly by a factor of 10. The degradation kinetics during creep was characterised quantitatively on the superalloy CMSX-4. A new non-destructive testing technique was applied to cover a wide test parameter range with few specimens in a relatively short time: repeated load annealing of wedge shaped specimens. KW - Creep damage KW - Nickel-base superalloys KW - Low-cycle fatigue KW - Rafting KW - Porosity KW - Prior exposure PY - 2010 DO - https://doi.org/10.3184/096034009X12603595726283 SN - 0960-3409 VL - 27 IS - 1 SP - 53 EP - 59 PB - Science Reviews CY - St. Albans, Herts. [u.a.] AN - OPUS4-23912 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fedelich, Bernard A1 - Künecke, Georgia A1 - Epishin, A. A1 - Link, T. A1 - Portella, Pedro Dolabella T1 - Constitutive modelling of creep degradation due to rafting in single-crystalline Ni-base superalloys N2 - A constitutive model for the mechanical behaviour of single-crystalline superalloys at high temperatures has been developed. The model relies on the slip system theory and is able to predict rafting and its influence on plastic flow. The kinetics of rafting are assumed to be driven by the reduction of the internal stresses represented by the macroscopic back-stress. The rafting effect is incorporated in the model through the dependence of the Orowan stress on the channel width. The model has been validated for the alloy CMSX-4 at 950 °C. The rafting part of the model has been calibrated by measurements of the channel widths after several levels of creep strains and for several loads. KW - Single crystal superalloy KW - Creep KW - Rafting KW - Constitutive modelling KW - Viscoplasticity PY - 2009 DO - https://doi.org/10.1016/j.msea.2008.04.089 SN - 0921-5093 SN - 1873-4936 VL - 510-511 SP - 273 EP - 277 PB - Elsevier CY - Amsterdam AN - OPUS4-19353 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nadammal, Naresh A1 - Kromm, Arne A1 - Saliwan Neumann, Romeo A1 - Farahbod, Lena A1 - Haberland, Christoph A1 - Portella, Pedro Dolabella T1 - Influence of support configurations on the characteristics of selective laser-melted Inconel 718 N2 - Samples fabricated using two different support configurations by following identical scan strategies during selective laser melting of superalloy Inconel 718 were characterized in this study. Characterization methods included optical microscopy, electron back-scattered diffraction and x-ray diffraction residual stress measurement. For the scan strategy considered, microstructure and residual stress development in the samples were influenced by the support structures. However, crystallographic texture intensity and the texture components formed within the core part of the samples were almost independent of the support. The formation of finer grains closer to the support as well as within the columnar grain boundaries resulted in randomization and texture intensity reduction by nearly half for the sample built on a lattice support. Heat transfer rates dictated by the support configurations in addition to the scan strategy influenced the microstructure and residual stress development in selective laser-melted Inconel 718 samples. KW - Additive manufacturing KW - Selective laser melting KW - Support configurations KW - Microstructure and texture KW - Residual stress PY - 2018 DO - https://doi.org/10.1007/s11837-017-2703-1 SN - 1047-4838 SN - 1543-1851 VL - 70 IS - 3 SP - 343 EP - 348 PB - Springer CY - USA AN - OPUS4-44175 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epishin, A. A1 - Link, T. A1 - Klingelhöffer, Hellmuth A1 - Fedelich, Bernard A1 - Brückner, Udo A1 - Portella, Pedro Dolabella T1 - New technique for characterization of microstructural degradation under creep: Application to the nickel-base superalloy CMSX-4 N2 - A new experimental technique (repeated load annealing of flat wedge shaped specimens) was proposed for characterization of microstructural degradation under creep conditions. This technique was applied to investigate the microstructural degradation of the nickel-base superalloy CMSX-4 in a wide range of temperatures and stress levels. The results obtained allowed to describe analytically the kinetics of rafting, which is important to predict the reduction of fatigue lifetime and yield stress. KW - Microstructural degradation KW - Nickel-base superalloys KW - Rafting PY - 2009 DO - https://doi.org/10.1016/j.msea.2008.04.135 SN - 0921-5093 SN - 1873-4936 VL - 510-511 SP - 262 EP - 265 PB - Elsevier CY - Amsterdam AN - OPUS4-19354 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Brückner, Udo A1 - Epishin, Alexander A1 - Link, T. A1 - Fedelich, Bernard A1 - Portella, Pedro Dolabella ED - Denis, S. T1 - Dendritic stresses in Nickel-base superalloys T2 - 7th International Conference on Residual Stresses CY - Xi'an, China DA - 2004-06-14 KW - Single crystal KW - Superalloy KW - Dendritic structure KW - Residual stresses KW - X-ray diffraction KW - Nickelbasis-Superlegierung KW - Dendritisches Gefüge KW - Röntgenbeugung PY - 2005 SN - 0-87849-969-5 SN - 0255-5476 N1 - Serientitel: Materials science forum – Series title: Materials science forum IS - 490/491 SP - 497 EP - 502 PB - Trans Tech Publ. CY - Uetikon-Zürich AN - OPUS4-7148 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -