TY - CONF A1 - Bruno, Giovanni A1 - Serrano Munoz, Itziar A1 - Fernandez, R. A1 - Gonzalez-Doncel, G. A1 - Garces, G. T1 - A paradigm shift in the description of creep in metals can only occur through multi-scale imaging N2 - The description of creep in metals has reached a high level of complexity; fine details are revealed by all sorts of characterization techniques and different theoretical models. However, to date virtually no fully microstructure-driven quantitative description of the phenomenon is available. This has brought to interesting inconsistencies; the classic description of (secondary) creep rests on the so-called power law, which however: a- has a pre-factor spanning over 10 orders of magnitude; b- has different reported exponents for the same material; c- has no explanation for the values of such exponents. Recently, a novel description (the so-called Solid State Transformation Creep (SSTC) Model) has been proposed to tackle the problem under a different light. The model has two remarkable features: 1- it describes creep as the accumulation of elementary strains due to dislocation motion; 2- it predicates that creep is proceeding by the evolution of a fractal arrangement of dislocations. Such description, however, needs a great deal of corroborating evidence, and indeed, is still incomplete. To date, we have been able to observe and somehow quantify the fractal arrangement of microstructures through Transmission Electron Microscopy (TEM), observe the accumulation of dislocations at grain boundaries by EBSD-KAM (Electron Back-Scattered Diffraction-Kernel Angular Misorientation) analysis, quantify the kinetic character (solid state transformation) of experimental creep curves, and estimate the sub-grain size of the fractal microstructure through X-ray refraction techniques. All pieces of the mosaic seem to yield a consistent picture: we seem being on the right path to reconstruct the whole elephant by probing single parts of it. What is still missing is the bond between the various scales of investigation. T2 - Korrelative Materialcharakterisierung 2022 CY - Dresden, Germany DA - 13.10.2022 KW - X-ray refraction KW - EBSD KW - Alloys KW - TEM KW - SEM PY - 2022 AN - OPUS4-56163 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Quantitative Microstructural Analysis - VAMAS TWA 37 & Liaison with ISO/TC 202 Microbeam Analysis N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects. The recently started project FIB sample processing for TEM is highlighted. Need of more promotion for the engagement of more participants from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed. Further, a short overview of the VAMAS areas of activities is given where Germany is involved. Planed regional VAMAS Workshops in Germany in 2023 are announced. T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 47th Steering Committee Meeting CY - Torino, Italy DA - 18.10.2022 KW - VAMAS KW - Microbeam analysis KW - FIB KW - TEM KW - Sample preparation KW - EBSD PY - 2022 UR - https://amdgroup.inrim.it/events/vamas-sc-meeting-47 AN - OPUS4-56146 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Liaison report from VAMAS with ISO/TC 202 Microbeam Analysis N2 - The progress in the activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects/inter-laboratory comparisons. The recently started project FIB sample processing for TEM is presented. Next projects in the pipeline involving EBSD and TKD are shortly announced. The need of more promotion for the engagement of more experts from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed. T2 - 29th Annual Meeting of ISO/TC 202 Microbeam Analysis CY - Online meeting DA - 28.11.2022 KW - VAMAS KW - ISO/TC 202 KW - Microbeam Analysis KW - EBSD KW - Electron microscopy KW - Thin films PY - 2022 AN - OPUS4-56424 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Report ISO/TC202/WG4 X-Ray Spectroscopy, Liaisons with VAMAS and ISO/TC229 Nanotechnologies N2 - The presentation is structured in the following three parts: i) Report of the Working Group 4 X-Ray Spectroscopy including the publication of ISO 15632:2021 Microbeam analysis — Selected instrumental performance parameters for the specification and checking of energy-dispersive X-ray spectrometers for use in electron probe microanalysis, ii) Liaison activities between ISO/TC202 Microbeam Anaylsis and VAMAS/TWA34 Quantitative Microstructural Analysis, and iii) Liaison activities from ISO/TC202 Microbeam Analysis for ISO/TC229 Nanotechnologies. Most relevant projects are highlighted for information and further discussions. New initiatives and better promotion of strategic projects are addressed. T2 - Annual Meeting of ISO/TC 202 Microbeam Analysis CY - Online meeting DA - 25.10.2021 KW - Microbeam Analysis KW - VAMAS KW - ISO/TC 202 KW - ISO/TC 229 KW - electron microscopy KW - X-Ray Spectroscopy KW - EBSD KW - FIB PY - 2021 AN - OPUS4-53625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - VAMAS TWA 37 - Quantitative Microstructural Analysis & Liaison with ISO/TC 202 Microbeam Analysis, Liaison with ISO N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects. Need of more promotion for the engagement of more participants from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed. Further, a short overview of the VAMAS areas of activities is given where Germany is involved. T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 46th Steering Committee Meeting CY - Online meeting DA - 08.09.2021 KW - VAMAS KW - Nanoparticles KW - Standardisation KW - Inter-laboratory comparison KW - ISO/TC 202 KW - ISO/TC 229 KW - ISO/TC 201 KW - Microstructure KW - EBSD PY - 2021 UR - http://www.vamas.org/twa/ AN - OPUS4-53237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded T1 - Observations of the deuterium distribution and the structural changes in standard and lean duplex stainless steels by ToF-SIMS and EBSD N2 - Duplex (DSS) and austenitic stainless steels (ASS) are frequently used in many energy related applications. The duplex grade is considered to have outstanding mechanical properties as well as good corrosion resistance. The austenitic phase combines high ductility, even at low temperatures, with sufficient strength, and therefore such materials are applied in storage and transport of high-pressure hydrogen. During service in acidic environments large amounts of hydrogen can ingress into the microstructure and induce many changes in the mechanical properties of the steel. Embrittlement of steels by hydrogen remains unclear even though this topic has been intensively studied for several decades. The reason for that lies in the inability to validate the proposed theoretical models in the sub-micron scale. Among the very few available methods nowadays, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) enables a highly accurate mapping of hydrogen in the microstructure in a spatial resolution below 100 nm. In the present work ToF-SIMS was used as a main tool in order to investigate the effect of deuterium on a duplex microstructure of lean and standard DSSs during and after the electrochemical charging process. Electrochemical charging simulates the service of a component in acidic environments under conditions of cathodic protection that are commonly applied to prevent corrosion reactions. ToF-SIMS after multivariate data analysis (MVA) was combined with high resolution topographic images and electron back-scattered diffraction (EBSD) data to characterize the structural changes. It was observed that the ferritic phase was affected almost identical in all steels whereas in the austenitic phase significant differences were obtained in the lean duplex in comparison to the standard DSS. The obtained results have been compared to similar investigations on a AISI 304L austenitic stainless steel. The advantage of the combined techniques is reflected by the ability to correlate the hydrogen distribution in the microstructure and the resulted phase transformation. T2 - Third International Conference on Metals & Hydrogen CY - Ghent, Belgien DA - 29.05.2018 KW - Data-fusion KW - ToF-SIMS KW - PCA KW - DSS KW - LDX KW - EBSD PY - 2018 AN - OPUS4-45094 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Quantitative Microstructural Analaysis under VAMAS/TWA 37 N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects. Need of more promotion for the engagement of more participants from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed. T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 45th Steering Committee Meeting CY - Online meeting DA - 30.09.2020 KW - VAMAS KW - Microbeam analysis KW - Inter-laboratory comparison KW - EBSD KW - FIB PY - 2020 UR - http://www.vamas.org/ AN - OPUS4-51360 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Czediwoda, Fabian A1 - Fedelich, Bernard A1 - Stöhr, B. A1 - Göhler, T. A1 - Völkl, R. A1 - Nolze, Gert A1 - Glatzel, U. T1 - A numerical approach to model high-temperature creep behaviour of Ni-base superalloys from microstructural morphology to grain size scales N2 - A constitutive model for the mechanical behaviour of single crystal Ni-base superalloys under high temperature conditions has been developed in the framework of a Cooretec project in cooperation with Siemens AG, MTU Aero Engines AG and University Bayreuth. In addition to the conventional material properties e.g. elastic constants, the model requires the parameters of the initial microstructure as an input. Thus, the γ’-precipitate size and the channel width of the γ-matrix were obtained from SEM micrographs. The model uses the slip system theory and describes the movement, multiplication and annihilation of dislocations in the channels. Furthermore, the cutting of precipitates is another mechanism contributing to the plastic flow. The evolution of the morphology due to rafting and its effects on the deformation have been implemented according to. The kinematic hardening is introduced as a stress tensor to realistically represent the strain hardening of arbitrary oriented single crystals. The mechanical behaviour of single crystal specimens has been experimentally investigated in tension tests at different strain rates and in creep tests under various loads. The constitutive model has been calibrated based on the experimental data for temperatures of 950°C and 850°C and the [001] and [111] crystallographic orientations. Finally, a micromechanical model was created to simulate the creep response of additive manufactured polycrystalline structures. An EBSD image is taken to obtain the grain geometry and their respective orientation. The grain boundaries are discretised using cohesive elements, whereas the single crystal model was applied to each grain in the representative volume. The polycrystal model is generated using Dream3D, NetGen and other software previously developed at the BAM. T2 - 6th European Conference on Computational Mechanics (ECCM 6) CY - Glasgow, UK DA - 11.06.2018 KW - Nickel-base superalloy KW - Creep KW - Rafting KW - Viscoplasticity KW - EBSD KW - Grain boundaries PY - 2018 AN - OPUS4-46973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded A1 - Straub, Franka A1 - Nolze, Gert A1 - Wirth, Thomas A1 - Boellinghaus, Thomas A1 - Unger, Wolfgang T1 - Observations of the deuterium distribution and the structural changes in standard and lean duplex stainless steels by ToF-SIMS and EBSD N2 - The use of duplex stainless steels (DSS) in energy related applications is well known. Nowadays, DSSs become more favorable than austenitic steels due to the outstanding mechanical properties, the good corrosion resistance and the lower nickel content.However, the use of the duplex grade in acidic environments such as seawater can lead to a severe degradation in the structural integrity of the steel by hydrogen-induced/assisted cracking mechanisms, which can eventually result in premature failure. Hydrogen assisted degradation and cracking of steels remains unclear even though this topic is intensively studied for more than a century. The main gap lies in the validation of the proposed theoretical models at the sub-micron scale. Industrial and the research communities define a need for an accurate method by which it is possible to image the distribution of hydrogen in the microstructure. Among the very few available methods nowadays, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) provides precise mapping of hydrogen in the microstructure. Moreover, the powerful combination of ToF-SIMS with multivariate data analysis (MVA), electron backscattered diffraction (EBSD) for providing a the structural information and the use of data fusion techniques can contribute to a better understanding of the hydrogen induced degradation processes in the material. In the present work two types of duplex grades were chosen as a case study (standard and lean DSS). The duplex class, consist of equivalent amounts of ferrite and austenite, was investigated by ToF-SIMS and EBSD during and after electrochemical deuterium charging in order to simulate the service of a component in acidic environments. Deuterium is known to act on the steel similarly to hydrogen and therefore was used as a tracer for hydrogen. The results show that the ferrite was affected almost identical in both steels whereas in the austenitic phase significant differences were observed in the lean duplex in comparison to the standard duplex. The advantage of the combined techniques is reflected by the ability to correlate the hydrogen distribution in the microstructure to the resulted structural changes. T2 - 21st International Conference on Secondary Ion Mass Spectrometry - SIMS21 CY - Krakow, Poland DA - 10.09.2017 KW - ToF-SIMS KW - Duplex-steel KW - EBSD KW - Data-fusion PY - 2017 UR - http://sims.confer.uj.edu.pl/boa_oral.php?id=23 AN - OPUS4-42864 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded T1 - Hydrogen assisted cracking phenomena in duplex stainless steels elucidated by in- and ex-situ ToF-SIMS experiments N2 - In the presented research, the high potential and abilities of secondary ion mass spectrometry (ToF-SIMS) to detect and locally map the hydrogen distribution in two types of duplex stainless steels are shown. The research validates certain proposed mechanisms by combining ToF-SIMS with high-resolution scanning electron microscopy and electron-backscattered diffraction. The combination of data from several techniques on the same region was conducted in this field for the first time by applying data treatment of the ToF-SIMS raw data and data fusion approach. This powerful combination of methods allows reviewing of the occurring processes related to hydrogen assisted cracking. The step beyond the state of the art in this field was gained here by developing permeation and mechanical loading experiments within the ToF-SIMS during chemometric imaging of the hydrogen distribution in the microstructure. The research presents the necessary correlation between the hydrogen distribution and the resulted structural changes, the diffusion behavior in a duplex microstructure and stress induced diffusion of hydrogen by applying external load at the microscale. T2 - 6th WMRIF Early Career Scientist Summit CY - NPL Teddington UK DA - 18.06.2018 KW - ToF-SIMS KW - Duplex stainless steel KW - LDX KW - EBSD KW - Data-fusion PY - 2018 AN - OPUS4-46865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Quantitative Microstructural Analysis - VAMAS TWA 37 & Liaison with ISO/TC 202 Microbeam Analysis N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the identification and launching corresponding VAMAS projects. The ongoing project "FIB sample processing for TEM" is presented in detail. T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 48th Steering Committee Meeting CY - New Delhi, India DA - 9.10.2023 KW - TEM KW - FIB KW - EBSD KW - Sample preparation KW - VAMAS KW - Standardisation KW - Interlaboratory comparisons PY - 2023 UR - https://www.nplindia.org/index.php/amcsnzt_2023/ AN - OPUS4-58538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sonntag, Nadja A1 - Jürgens, Maria A1 - Roohbakhshan, Farshad A1 - Agudo Jácome, Leonardo A1 - Olbricht, Jürgen T1 - Dwell-Fatigue and Cyclic Softening of Grade P92 Steel under LCF and TMF Conditions N2 - Tempered martensite-ferritic steels, such as the grade P92 steel studied in this contribution, exhibit pronounced macroscopic cyclic softening under isothermal low-cycle fatigue (LCF) and non-isothermal thermomechanical fatigue (TMF) conditions, which is considered to be the predominant degradation mechanism in high-temperature fatigue in this and other material groups. However, such softening processes are highly complex since microscopic (e.g., recovery) and macroscopic (e.g., crack initiation and growth), as well as global and local effects superimpose, especially under creep-fatigue conditions. In this contribution, we discuss the cyclic deformation and softening behavior of P92 in strain-controlled LCF, in-phase (IP) TMF, and out-of-phase (OP) TMF tests with and without dwell times in the temperature range from 300 °C to 620°C. EBSD-based dislocation analysis on various fatigued material states confirms the continuous redistribution and annihilation of geometrically necessary dislocations in all studied states, which can be quantitatively correlated with macroscopic softening despite different damage mechanisms for different test types. Deviations from this correlation are observed for OP TMF and LCF with dwell times, i.e., for conditions where optical microscopy reveals pronounced crack-oxidation interactions at the specimen surfaces. T2 - LCF9 - Ninth International Conference on Low Cycle Fatigue CY - Berlin, Germany DA - 21.06.2022 KW - LCF KW - TMF KW - EBSD PY - 2022 DO - https://doi.org/10.48447/LCF9-2022-111 AN - OPUS4-55128 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - (Pre)Standardisation and Metrology in Microbeam Analysis – Ongoing Activities and Opportunities N2 - The presentation addresses the current ongoing projects as well as the gaps and opportunities in microbeam analysis within ISO/TC 202 Microbeam Analysis standardisation body and in-liaison Technical Working Areas (TWAs) at the pre-standardization platform of VAMAS (Versailles Project on Advanced Materials and Standards). T2 - EMAS 2023 - 17th European Workshop on Modern Developmennts and Applications in Microbeam Analysis - General Assembly CY - Krakow, Poland DA - 07.05.2023 KW - Microbeam analysis KW - EDS KW - Electron microscopy KW - Inter-laboratory comparison KW - EBSD KW - Standardisation PY - 2023 AN - OPUS4-57483 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nolze, Gert A1 - Tokarski, T. T1 - Lattice parameter determination with EBSD. Is that possible? N2 - CALM is software for determining the Bravais lattice type and the resulting lattice parameters from a single Kikuchi pattern. It requires the definition of 4 bands and a single bandwidth from which all other band positions as well as bandwidths are derived. For band detection, it uses the Funk transform, which allows detection of twice as many bands as usual. CALM works for any symmetry and requires low-noise patterns of at least 320x240 pixels. The resulting errors are <2% even for such small patterns, assuming good quality. The relative errors are <0.5%. However, this requires a projection centre position best derived from a sample of a cubic phase in CALM. However, this must have been recorded under identical conditions. Hundreds of Kikuchi patterns of phases with different symmetries were examined. T2 - Institutskolloquium Kassel CY - Online meeting DA - 30.10.2020 KW - Phasenidentifikation KW - EBSD KW - Gitterkonstanten PY - 2020 AN - OPUS4-51813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nolze, Gert A1 - Tokarski, T. T1 - CALM down: Identifying unknown phases N2 - CALM is software for determining the Bravais lattice type and the resulting lattice parameters from a single Kikuchi pattern. It requires the definition of 4 bands and a single bandwidth from which all other band positions as well as bandwidths are derived. For band detection, it uses the Funk transform, which allows detection of twice as many bands as usual. CALM works for any symmetry and requires low-noise patterns of at least 320x240 pixels. The resulting errors are <2% even for such small patterns, assuming good quality. The relative errors are <0.5%. However, this requires a projection centre position best derived from a sample of a cubic phase in CALM. However, this must have been recorded under identical conditions. Hundreds of Kikuchi patterns of phases with different symmetries were examined. T2 - Chemnitz MTEX Workshop 2021 CY - Online meeting DA - 08.03.2021 KW - EBSD KW - Gitterkonstanten KW - Phasenidentifikation PY - 2021 AN - OPUS4-52345 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Suárez Ocano, Patricia A1 - Fries, S. G. A1 - López-Galilea, I. A1 - Ruttert, B. A1 - Theisen, W. A1 - Agudo Jácome, Leonardo T1 - Microstructural characterization of the AlMo 0.5 NbTa 0.5 ZrTi refractory complex concentrated alloy N2 - A set of some unexpected and interesting microstructures has put the so-called complex concentrated alloys (CCAs) in the eye of the scientific community and the AlMo0.5NbTa0.5TiZr refractory (r)CCA, aimed at substituting Ni-base superalloys in gas turbine applications, belongs to this alloy family. The AlMo0.5NbTa0.5TiZr rCCA was studied by SEM, EDX, EBSD and TEM, showing the presence of a nanoscopic basket-wave structure inside the grains, with two BCC phases. Additionally, thermodynamic calculations on the AlMo0.5NbTa0.5TiZr alloy were done with two different proprietary databases that anticipate two BCC-disordered phases with distinct constitutions as well as an HCP phase. T2 - Symposium on Advanced Mechanical and Microstructural Characterization of High-Entropy Alloys CY - Bochum, Germany DA - 03.02.2020 KW - High Entropy Alloy KW - EBSD KW - Microstructure Characterization PY - 2020 AN - OPUS4-50729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -