TY - CONF A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Bettge, Dirk A1 - Kratzig, Andreas A1 - Knauer, S. T1 - Factors Influencing Droplet Corrosion in Dense Phase CO2 T2 - Proceedings NACE International Corrosion Conference 2019 N2 - Recent studies have shown that even at a very low concentration of impurities (less than 100 ppmv of SO2, NO2, O2 and H2O) the droplet formation and condensation of sulfuric and nitric acids in dense phase CO2 are possible and observable. To reveal the mechanism of droplet corrosion in dense phase CO2 at high pressure and low temperature, further studies on factors that affect wettability and resulting corrosion behaviors of transport pipeline steels are needed. In this study, effects of surface morphology were investigated by varying surface roughness of carbon steel coupons exposed to CO2 stream containing impurities to measure the wettability by contact angle and to observe the condensation as well as possible droplet corrosion that followed. Other considered factors were: pH of the droplet, temperature, droplet volume, and exposure time. T2 - NACE International Corrosion Conference 2019 CY - Nashville, TN, USA DA - 24.03.2019 KW - CCUS KW - Dense phase KW - CO2 KW - Droplet KW - Corrosion KW - Condensation KW - Carbon steel PY - 2019 SP - 13017-1 EP - 13017-13 PB - NACE International CY - Houston AN - OPUS4-47915 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hemmleb, M. A1 - Bettge, Dirk ED - Petzow, G. T1 - In-situ Messung der 3D-Topografie von Bruchflächen im REM T2 - Fortschritte in der Metallographie N2 - Die Abbildung von Bruchflächen im Rasterelektronenmikroskop (REM) liefert hochaufgelöste Bilddaten, die für die mikrofraktografische Bewertung von Bruchmechanismen unerlässlich sind. Die Ermittlung von Bruchmechanismen ist oft ein wichtiger Teil von Schadensanalysen zur Ermittlung der Bruchursache. Durch den Abbildungsprozess im REM gehen räumliche Informationen im Normalfall größtenteils verloren und können daher nicht zur Präzisierung des Bruchmechanismus herangezogen werden. Um räumliche Informationen von Probenoberflächen im REM zu erfassen, gibt es verschiedene Methoden. Die für die Ermittlung der 3D-Topografie bereits länger eingeführten Verfahren mittels Proben- oder Strahlkippung können die Berechnung des Oberflächenmodells erst nach der seriellen Aufnahme mehrerer Bilder vornehmen. Mit der Verwendung eines segmentierten Rückstreudetektors ist dagegen die Erzeugung eines 3D-Oberflächenmodells während der Bildaufnahme praktisch in Echtzeit möglich. Die Probentopografie wird gleichzeitig mit dem Bildeinzug dargestellt und gespeichert. T2 - Metallographietagung 2019 CY - Dresden, Germany DA - 18.09.2019 KW - Fraktografie KW - Schadensanalyse KW - Topografie KW - 3D KW - REM PY - 2019 SN - 978-3-88355-417-4 VL - 2019/53 SP - 175 EP - 180 PB - DGM AN - OPUS4-49332 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sommer, Konstantin A1 - Ávila, Luis T1 - Microstructure ageing of stainless steel AISI 316L manufactured by selective laser melting (SLM) N2 - Additive manufacturing (AM) processes, such as SLM, offer a variety of advantages compared to conventional manufacturing. Today AM parts are still comparatively less cost-effective if they are manufactured in large quantities. To make the AM parts more cost-efficient, the AM process has to be improved. It requires a good understanding of microstructure formation, microstructure-property-relations and ageing processes affected by different loads. In this work the ageing behavior of SLM manufactured AISI 316L stainless steel is evaluated. The microstructure effected by mechanical, thermal and corrosive loads are investigated and compared to as-built microstructure. Tensile tests are used for mechanical ageing. For thermal and corrosive loads the typical application conditions of 316L apply. The methods of microstructure investigation include SEM, TEM, CT and EBSD. The main object of this work is the description of microstructure and ageing processes of AM parts. T2 - European Conference on Structural Integrity of Additively Manufactured Materials (ESIAM) 2019 CY - Trondheim, Norway DA - 09.09.2019 KW - 316L KW - Selective laser melting KW - Microstructure evolution PY - 2019 AN - OPUS4-49886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Wencke A1 - Stephan-Scherb, Christiane A1 - Laplanche, Guillaume T1 - High temperature oxidation behavior of CrMnFeCoNi and CrCoNi in various atmospheres N2 - The study presented here focusses on a systematic analysis of oxidation mechanisms of the well-known Cr20Mn20Fe20Co20Ni20 alloy and one of its ternary sub-system Cr33.3Co33.3Ni33.3 which were reported in the literature to exhibit attractive mechanical properties. Both alloys are single phase fcc prior to oxidation and were simultaneously exposed to different oxygen containing atmospheres at 700° C and 800° C for durations up to 288 h. Cr20Mn20Fe20Co20Ni20 showed poor oxidation resistance at high temperatures due to its high amount of manganese leading to the formation of non-protective Mn-oxide scales. In contrast, a relatively homogeneous and protective chromia layer was found to form on CrCoNi at 700° C and 800° C after each exposure time. Mass change-, SEM- and XRD analysis of the oxide layers were performed in the present study and provide a better understanding of the oxidation mechanisms as well as the impact of the alloy composition on oxidation behavior. T2 - World Congress on High Entropy Alloys (HEA 2019) CY - Seattle, WA, USA DA - 17.11.2019 KW - Scanning electron microscopy KW - High-entropy alloys KW - High-temperature corrosion PY - 2019 AN - OPUS4-50309 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stephan-Scherb, Christiane T1 - Elucidation of Surface Degradation Phenomena By In Situ X-ray techniques N2 - Presentation of in situ and real time approaches to study high temperature oxidation phenomena by adavnced X-ray techniques. Application to the analysis of degradation mechanisms of chemical complex alloys and high entropy alloys was presented. T2 - SPP 2006 Hot Topic Meeting "Large Scale Facility Based Techniques CY - Helmholtz-Zentrum Berlin für Materialien und Energie, Germany DA - 26.09.2019 KW - High entropy alloys KW - Diffraction KW - In situ KW - Oxidation PY - 2019 AN - OPUS4-49134 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Schiller, B.N A1 - Beck, M. A1 - Bettge, Dirk T1 - On the corrosion behaviour of CO2 injection pipe steels: Role of cement N2 - Carbon Capture and Storage (CCS) is identified as an excellent technology to reach the target of CO2 reduction. However, the safety issue and cost-effectiveness hinder the future of CCS. For the reliability and safety issues of injection wells, the corrosion resistance of the materials used needs to be determined. In this study, representative low-cost materials including carbon steel 1.8977 and low alloyed steel 1.7225 were investigated in simulated pore water at 333 K and under CO2 saturation condition to represent the worst-case scenario: CO2 diffusion and aquifer fluid penetration. These simulated pore waters were made from relevant cement powder to mimic the realistic casing-cement interface. Electrochemical studies were carried out using the pore water made of cement powder dissolved in water in comparison with those dissolved in synthetic aquifer fluid, to reveal the effect of cement as well as formation water on the steel performance. Two commercially available types of cement were investigated: Dyckerhoff Variodur® and Wollastonite. Variodur® is a cement containing high performance binder with ultra-fine blast furnace slag which can be used to produce high acid resistance concrete. On the other hand, Wollastonite is an emerging natural material mainly made of CaSiO3 which can be hardened by converting to CaCO3 during CO2 injection. The results showed the pH-reducing effect of CO2 on the simulated pore water/aquifer (from more than 10 to less than 5) leading to the active corrosion process that happened on both 1.8977 and 1.7225. Electrochemical characterization showed negative free corrosion potential and polarisation curves without passive behaviors. The tested coupons suffered from pitting corrosion, which was confirmed by surface analysis. Interestingly, basing on the pit depth measurements from the tested coupons and the hardness of cement powder, it is suggested that Variodur® performed better than Wollastonite in both aspects. The electrochemical data was compared to that resulted from exposure tests to give a recommendation on material selection for bore-hole construction. T2 - EUROCORR 2019 CY - Sevilla, Spain DA - 09.09.2019 KW - Carbon capture KW - Utilization, and storage (CCUS) technology KW - Corrosion KW - Carbon steel KW - Mortel KW - Crevice corrosion PY - 2019 AN - OPUS4-49105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falk, Florian A1 - Stephan-Scherb, Christiane A1 - Lehmusto, J. A1 - Pint, B. T1 - The impact of water vapour on high-temperature surface degradation by sulfurous gases of ferritic alloys N2 - Sulfur and water have a fundamental impact on the corrosion rate and potential failure of materials. It is therefore necessary to understand the mechanisms, rates, and potential means of transport, as well as the reactions of these elements with an alloy. This work investigates the effect of water vapor in the initial stages of SO2 corrosion of an ferritic model alloy containing 9 wt% Cr and 0.5 wt% Mn. The exposure experiments were studied at 650°C in situ under laboratory conditions using energy-dispersive x-ray diffraction analysis. Two separate experiments were run, one with a 99.5% Ar + 0.5% SO2 atmosphere and one with a 69.5% Ar + 0.5% SO2 + 30% H2O atmosphere. With a wet atmosphere, the alloy formed a scale with decreasing oxygen content towards the scale–alloy interface. Sulfides were identified above and below a (Fe, Cr)3O4 layer in the inner corrosion zone. In contrast to this, the overall scale growth was slower in a dry SO2 atmosphere. T2 - EUROCORR CY - Barceló Sevilla Renacimiento, Seville, Spain DA - 09.09.2019 KW - Diffraction KW - Sulfidation KW - Early oxidation KW - Corrosion KW - In situ PY - 2019 AN - OPUS4-49213 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Suárez Ocano, Patricia A1 - Fries, S. A1 - Agudo Jácome, Leonardo T1 - Thermodynamic study of a refractory complex concentrated alloy using the CALPHAD method N2 - Introduction/purpose: Multi-principal-element alloys (MPEAs), also known as complex concentrated alloys (CCAs), have recently come to the attention of the scientific community due to some interesting and unexpected microstructures, and their potential for improving properties such as, e.g. mechanical strength and oxidation resistance in high temperature structural applications. The AlMo0.5NbTa0.5TiZr refractory (r)CCA is one such candidate, showing a two-phase microstructure after a two-stage heat treatment under argon atmosphere at a controlled cooling rate. Since the application conditions intended for this alloy require a long-term high temperature (> 700 °C) mechanical and oxidation resistance, it becomes necessary to assess the possible phase development in this regime. Methods: In this contribution, the CALPHAD method is used to calculate phase equilibria for the AlMo0.5NbTa0.5TiZr CCA in the presence and absence of oxygen. Equilibrium phase amount evolution with temperature and Scheil Model for solidification (e.g. Fig.1a and Fig.1b, respectively) are analyzed, which are obtained using the databases TCNI9 and TTNI7 and the Gibbs energy minimizer in the Thermo-Calc software. Results: The diagrams reveal that two BCC-based phases could form during alloy solidification, where one phase would be enriched with Mo, Nb and Ta while the other phase, with Al, Ti and Zr. Activity oxides diagrams show that a stable form of aluminum oxide (α-Al2O3, Pearson symbol: hR10, corundum) can be formed. Results obtained by both databases, as well as discrepancies between property phase and Scheil approaches are discussed on the base of experimental results. Conclusions: A modeling tool is used to support alloy characterization and development, providing also the possibility to feedback information to improve existing thermodynamic databases. T2 - EUROMAT 2019 CY - Stockholm, Sweden DA - 01.09.2019 KW - CALPHAD databases analysis KW - Thermodynamic analysis KW - Complex concentrated alloy (CCA) PY - 2019 AN - OPUS4-49345 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hemmleb, M. A1 - Bettge, Dirk T1 - In-situ Messung der 3D-Topografie von Bruchflächen im REM N2 - Die Abbildung von Bruchflächen im REM liefert hochaufgelöste Bilddaten, die für die mikrofraktografische Bewertung von Bruchmechanismen unerlässlich sind. Durch den Abbildungsprozess im REM gehen räumliche Informationen im Normalfall größtenteils verloren. Mit der Verwendung eines segmentierten Rückstreudetektors ist dagegen die Erzeugung eines 3D-Oberflächenmodells während der Bildaufnahme praktisch in Echtzeit möglich. Die hier beschriebene Untersuchung soll die Anwendbarkeit des Verfahrens auf Bruchflächen zeigen. Zukünftig können Topografiedaten dazu beitragen, Bruchflächen besser zu interpretieren. T2 - Metallographietagung 2019 CY - Dresden, Germany DA - 18.09.2019 KW - Fraktografie KW - Schadensanalyse KW - Topografie KW - 3D PY - 2019 AN - OPUS4-49330 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falk, Florian A1 - Stephan-Scherb, Christiane T1 - Microstructural impact on high temperature oxidation behavior of Fe-Cr-C model alloys N2 - Chromia forming high alloyed ferritic-austenitic steels are being used as boiler tube materials in biomass and coal-biomass co-fired power plants. Despite thermodynamic and kinetic boundary conditions, microstructural features such as grain orientation, grain sizes or surface deformation contribute to the oxidation resistance and formation of protective chromium-rich oxide layers. This study elucidates the impact of microstructure such as the grain size and number of carbide precipitates on high temperature oxidation at 650°C in 0.5% SO2 atmosphere. Cold-rolled Fe-16Cr-0.2C material was heat-treated to obtain two additional microstructures. After exposure to hot and reactive gases for 10 h < t < 1000 h layer thicknesses and microstructure of oxide scales are observed by scanning electron microscopy and Energy-dispersive X-ray spectroscopy. The two heat treated alloys showed reasonable oxidation resistance after 1000 h of exposure. The oxidation rate was substantially higher for the alloy with a duplex matrix after heat treatment compared to the fine-grained material. T2 - Gordon Research Conference CY - New London, New Hampshire, USA DA - 21.07.2019 KW - Corrosion KW - Microstructure KW - Oxidation KW - Sulfidation PY - 2019 AN - OPUS4-49212 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -