TY - CONF A1 - Han, Ying A1 - Kruse, Julius A1 - Madia, Mauro A1 - Radners, Jan A1 - von Hartrott, Philipp A1 - Skrotzki, Birgit T1 - The influence of aging and mean stress on fatigue of Al-alloy EN AW-2618A N2 - In this study, the influence of aging and mean stress on fatigue of the aluminium-alloy EN AW-2618A is investigated. Therefore axial fatigue tests are carried out on smooth specimens. The experiments show that the fatigue life decreases with increasing mean stress. Furthermore, the tests with the overaged specimens demonstrate that the number of cycles to failure is decreasing with increasing aging time. T2 - LCF9 CY - Berlin, Germany DA - 21.06.2022 KW - Fatigue KW - Aluminium alloy KW - EN AW-2618A KW - Damage Behavior PY - 2022 AN - OPUS4-55125 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Han, Ying A1 - Radners, J. A1 - von Hartrott, P. A1 - Skrotzki, Birgit T1 - Aluminium High Temperature Fatigue N2 - The studied aluminium alloy is EN AW-2618A (2618A). It is very widely used for exhaust gas turbo-charger compressor wheels. Due to long operating times, high cycle fatigue (HCF) and material aging under the influence of temperatures up to 230 °C is particularly relevant for the wheels. The wheels are typically milled from round wrought blanks. From such round blanks, different testpieces are extracted and a comprehensive series of HCF tests is conducted at room temperature. The tests investigate the materials fatigue performance in the T61 state for two load-ratios, namely R = -1 and R = 0.1. Additionally, two overaged material states are tested, accounting for the aging process the material undergoes during long operating times at high temperatures. The experimental results are evaluated and compared to each other. Furthermore, the design process of notched specimens is presented. With the notched specimens, it is aimed to quantify the notch sensitivity of the material. Relating thereto, two potential model parameters for the fatigue lifetime model are introduced. T2 - FVV Frühjahrstagung 2022 CY - Würzburg, Germany DA - 31.03.2022 KW - High Cycle Fatigue KW - Aluminium Alloy KW - EN AW-2618A PY - 2022 AN - OPUS4-54886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Han, Ying A1 - Radners, J. A1 - von Hartrott, P. A1 - Skrotzki, Birgit T1 - Aluminium high temperature fatigue T2 - Tagungsband der FVV-Informationstagung - Frühjahrstagung 2022 - Würzburg N2 - The studied aluminium alloy is EN AW-2618A (2618A). It is very widely used for exhaust gas turbo-charger compressor wheels. Due to long operating times, high cycle fatigue (HCF) and material aging under the influence of temperatures up to 230 °C is particularly relevant for the wheels. The wheels are typically milled from round wrought blanks. From such round blanks, different testpieces are extracted and a comprehensive series of HCF tests is conducted at room temperature. The tests investigate the materials fatigue performance in the T61 state for two load-ratios, namely R = -1 and R = 0.1. Additionally, two overaged material states are tested, accounting for the aging process the material undergoes during long operating times at high temperatures. The experimental results are evaluated and compared to each other. Furthermore, the design process of notched specimens is presented. With the notched specimens, it is aimed to quantify the notch sensitivity of the material. Relating thereto, two potential model parameters for the fatigue lifetime model are introduced. Finally, the extended research data management in this project is highlighted and its advantages for sustainable use in material science and engineering applications are shown. N2 - In diesem Projekt wird die Aluminiumlegierung EN AW-2618A (2618A) untersucht, welche sehr verbreitet in Verdichterrädern von Abgasturboladern zum Einsatz kommt. Hochzyklische Ermüdung und Werkstoffalterung bei Temperaturen von bis zu 230 °C ist bei Abgasturboladern aufgrund der langen Einsatzzeiten besonders relevant. Die Verdichterräder werden typischerweise aus geschmiedeten Rohlingen gefräst. Aus entsprechenden Rohlingen werden im Rahmen des Projekts eine Vielzahl von Proben mit unterschiedlichen Geometrien entnommen. Die Proben werden unter verschiedenen Prüfbedingungen in hochzyklischen Ermüdungsversuchen bei Raumtemperatur getestet. Zum einen wird das Ermüdungsverhalten des Werkstoffs im T61-Zustand für die zwei Belastungsverhältnisse R = -1 und R = 0,1 untersucht. Zum anderen werden zwei überalterte Materialzustände getestet. Damit soll dem Alterungsprozess Rechnung getragen werden, den das Material während langer Betriebszeiten bei hohen Temperaturen durchläuft. Die experimentellen Ergebnisse werden evaluiert und miteinander verglichen. Darüber hinaus wird der Entwurfsprozess von gekerbten Probengeometrien dokumentiert. Die gekerbten Proben sollen Aufschluss über die Kerbempfindlichkeit des Werkstoffs geben. In diesem Zusammenhang werden zwei mögliche Modellparameter für das zu entwickelnde Lebensdauermodell vorgestellt. Abschließend wird das erweiterte Forschungsdatenmanagement des Projekts beleuchtet und seine Vorteile für die nachhaltige Nutzung in materialwissenschaftlichen und ingenieurtechnischen Anwendungen aufgezeigt. T2 - FVV Frühjahrstagung 2022 CY - Würzburg, Germany DA - 31.03.2022 KW - EN AW-2618A KW - High cycle fatigue KW - Aluminium alloy PY - 2022 IS - FVV Publikationen Heft R602 SP - 617 EP - 634 PB - Forschungsvereinigung Verbrennungskraftmaschinen (FVV) CY - Frankfurt am Main AN - OPUS4-54622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Han, Ying A1 - Kruse, Julius A1 - Madia, Mauro A1 - Skrotzki, Birgit T1 - High cycle fatigue behavior of alloy EN AW-2618A N2 - The presentation shows the results of high cycle fatigue (HCF) tests from the aluminium alloy EN AW-2618A. This study investigates the mean stress influence in the T61 condition and the effect of overaging. For this purpose, axial HCF tests were carried out at room temperature and different stress ratios (R=-1, R=0.1) as well as with overaged conditions (T61+10h@230°C, T61+1000h@230°C). After completion of the tests, the fracture surfaces were examined to study crack initiation. T2 - The 18th International Conference on Aluminium Alloys CY - Toyama, Japan DA - 04.09.2022 KW - High Cycle Fatigue KW - Aluminium Alloy KW - EN AW-2618A PY - 2022 AN - OPUS4-55865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radners, Jan A1 - Han, Ying A1 - von Hartrott, Philipp A1 - Skrotzki, Birgit T1 - Aluminum High Temperature Fatigue T2 - The FVV Transfer + Networking Event | Information Sessions – Autumn 2023 N2 - The high operating temperatures of radial compressor wheels in exhaust gas turbochargers lead to a change in the original microstructure of the heat-resistant aluminum alloy EN AW-2618A (overaging). This is caused by thermal loads that are close to the age hardening temperature and can even exceed it for a short time. The aging mechanisms have been investigated together with low cycle fatigue (LCF), thermomechanical fatigue (TMF) and creep up to max. 190 °C in previous research projects. The be-havior of the alloy under high cycle fatigue (HCF) and the influence of load spectra have hardly been investigated. Since the operating temperatures of centrifugal compressors are expected to increase in the future, this research project investigated the HCF behavior at 230 °C, a test temperature significantly higher than the age hardening temperature. The objectives of the project were to establish a suitable experimental database, to understand the relevant microstructural processes, and to further develop and adapt suitable models and evaluation methods. In addition to a basic characterization of the HCF behavior in the initial condition T61, the experimental investigation program included targeted mechanical tests to isolate the influencing factors of mean stress (𝑅=−1, 𝑅=0.1), material overaging (T61, 10 h/230 °C, 1000 h/230 °C), test temperature (20 °C, 230 °C), test frequency (0.2 Hz, 20 Hz) as well as variable amplitudes. On this basis, the models and evaluation methods developed in the previous projects were adapted and further developed to reflect thermal and mechanical loads in the lifetime assessment. T2 - The FVV Transfer + Networking Event (Herbst 2023) CY - Würzburg, Germany DA - 04.10.2023 KW - Aluminum alloys KW - Fatigue KW - EN AW-2618A PY - 2023 SP - 1 EP - 30 AN - OPUS4-58562 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Han, Ying A1 - Kruse, Julius A1 - Rosalie, Julian A1 - Radners, J. A1 - von Hartrott, P. A1 - Skrotzki, Birgit T1 - Influence of mean stress and overaging on fatigue life of aluminum alloy EN AW-2618A JF - Materials Science & Engineering A N2 - Fatigue tests were performed on the forged aluminum alloy EN AW-2618A in the T61 state. Different stress ratios (R = -1, R = 0.1) were selected to study the influence of mean stress on fatigue life. Two overaged states (10 h/230 ◦C, 1000 h/230 ◦C) were also tested to investigate the influence of overaging on fatigue life. Transmission electron microscopy (TEM) was used to characterize the precipitates (S-phase), which are mainly responsible for the strength of the alloy. A fractographic analysis was also performed to determine the failure mode. Overaging reduces the fatigue life compared to the T61 state. The longer the aging time, the lower the fatigue resistance. The reason is the decrease in (yield) strength, which correlates with the radius of the S-phase: the precipitate radius increases by a factor of approximately two for the overaged states compared to the initial state. The analysis of the fracture surfaces showed crack initiation occurs predominantly on the outer surface and is associated with the primary phases. KW - Aluminum alloys KW - Aging KW - Fatigue KW - Microstructure KW - Electron microscopy KW - S-Phase PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583708 DO - https://doi.org/10.1016/j.msea.2023.145660 SN - 0921-5093 VL - 886 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-58370 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -