Coupled microscopic and micromagnetic depth-specific analysis of plastic deformation and phase transformation of metastable austenitic steel AISI 304L by flow forming
-
J. Rozo Vasquez
works as Scientific Assistant at the Chair of Materials Test Engineering (WPT) of the TU Dortmund University since May 2019. Within the investigation project “Property control during spinning of metastable austenites” funded by the German Research Foundation (DFG), he is concerned with the microstructural characterization by means of microscopic techniques, including EDS, EBSD and AFM.
works as Research Assistant at the Chair of Materials Test Engineering (WPT) of the TU Dortmund University since September 2020. In the course of the project she is responsible for the micromagnetic testing, hardness measurements and sample preparation for microscopic investigation.
Abstract
This paper presents the characterization of the microstructure evolution during flow forming of austenitic stainless steel AISI 304L. Due to plastic deformation of metastable austenitic steel, phase transformation from γ-austenite into α’-martensite occurs. This is initiated by the formation of shear bands as product of the external stresses. By means of coupled microscopic and micromagnetic investigations, a characterization of the microstructure was carried out. In particular, this study shows the distribution of the strain-induced α’-martensite and its influence on material properties like hardness at different depths. The microstructural analyses by means of electron backscattered diffraction (EBSD) technique, evidence a higher amount of α’-martensite (ca. 23 %) close to the outer specimen surface, where the plastic deformation and the direct contact with the forming tool take place. In the middle area (ca. 1.5 mm depth from the outer surface), the portion of transformed α’-martensite drops to 7 % and in the inner surface to 2 %. These results are well correlated with microhardness and micromagnetic measurements at different depths. EBSD and atomic force microscopy (AFM) were used to make a detailed characterization of the topography and degree of deformation of the shear bands. Likewise, the mechanisms of nucleation of α’-martensite were discussed. This research contributes to the development of micromagnetic sensors to monitor the evolution of properties during flow forming. This makes them more suitable for closed-loop property control, which offers possibilities for an application-oriented and more efficient production.
Kurzfassung
Dieser Beitrag beschäftigt sich mit der während des Drückwalzens in rostfreiem austenitischem Stahl AISI 304L ablaufenden Gefügeentwicklung. Durch plastische Verformung von metastabilem austenitischem Stahl kommt es zur Phasenumwandlung von γ-Austenit zu α’-Martensit. Diese wird ausgelöst infolge der sich aufgrund der äußeren Belastungen bildenden Scherbänder. In kombinierten mikroskopischen und mikromagnetischen Untersuchungen wurde das Gefüge charakterisiert. In diesem Beitrag wird insbesondere auf die Verteilung des spannungsinduzierten α’-Martensits und dessen Auswirkung auf Werkstoffeigenschaften, beispielsweise die Härte, in unterschiedlichen Tiefen eingegangen. Gefügeanalysen mittels Elektronenrückstreubeugung (EBSD) zeigen eine höhere Menge an α’-Martensit (ca. 23 %) in der Nähe der Probenaußenfläche, dort, wo die plastische Verformung erfolgt und ein direkter Kontakt mit dem Umformwerkzeug besteht. Im mittleren Bereich (ca. 1,5 mm Tiefe von der Außenfläche) fällt der Anteil von umgewandeltem α’-Martensit auf 7 %, an der Innenfläche bis auf 2 %. Diese Ergebnisse korrelieren gut mit den in Mikrohärte- und mikromagnetischen Messungen in unterschiedlichen Tiefen ermittelten Werten. Für eine eingehende Charakterisierung der Topographie und des Grads der Verformung der Scherbänder kamen EBSD und Atomkraftmikroskopie (AFM) zum Einsatz. Außerdem wurden die Keimbildungsmechanismen des α’-Martensits erörtert. Diese Forschungsarbeit leistet einen Beitrag zur Entwicklung mikromagnetischer Sensoren zur Überwachung der Entwicklung von Eigenschaften während des Drückwalzens. Deren Eignung für die Eigenschaftsregelung kann so verbessert werden, wodurch sich wiederum Möglichkeiten für eine anwendungsorientierte und effizientere Fertigung ergeben.
About the authors
works as Scientific Assistant at the Chair of Materials Test Engineering (WPT) of the TU Dortmund University since May 2019. Within the investigation project “Property control during spinning of metastable austenites” funded by the German Research Foundation (DFG), he is concerned with the microstructural characterization by means of microscopic techniques, including EDS, EBSD and AFM.
works as Research Assistant at the Chair of Materials Test Engineering (WPT) of the TU Dortmund University since September 2020. In the course of the project she is responsible for the micromagnetic testing, hardness measurements and sample preparation for microscopic investigation.
5 Acknowledgements
Funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) – project number 424335026 – within the priority program SPP 2183: “Property-Controlled Forming Processes”. The authors thank the German Research Foundation and the Ministry of Culture and Science of North Rhine-Westphalia (Ministerium für Kultur und Wissenschaft des Landes Nordrhein-Westfalen, MKW RW) for their financial support within the major research instrumentation program for the “In-situ-AFM”, project number 445052562.
5 Danksagung
Finanziert durch die Deutsche Forschungsgemeinschaft, DFG, Projektnummer 424335026, im Rahmen des Schwerpunktprogramms SPP 2183: „Eigenschaftsgeregelte Umformprozesse“. Die Autoren bedanken sich bei der Deutschen Forschungsgemeinschaft und dem Ministerium für Kultur und Wissenschaft des Landes Nordrhein-Westfalen, MKW RW) für die finanzielle Unterstützung im Rahmen des Forschungsgroßgeräteprogramms für die „in-situ-AFM“, Projektnummer 445052562.
References / Literatur
[1] Marini, D.; Cunninigham, D.; Xirouchakis, P.; Corney, J.: Flow forming: A review of research methodologies, prediction models and their applications, Int. J. Mech. Eng. 7, 5 (2016), pp. 285–315.Search in Google Scholar
[2] Astudillo, M.; Nicolás, M.; Ruzzante, J.; Gómez, M.; Ferrari, G.; Padovese, L.; Pumarega, M.: Correlation between martensitic phase transformation and magnetic Barkhausen noise of AISI 304 steel, Proc. Mat. Sci. 9 (2015), pp. 435–443. DOI: 10.1016/j.mspro.2015.05.01410.1016/j.mspro.2015.05.014Search in Google Scholar
[3] Rozo Vasquez, J.; Arian, B.; Riepold, M.; Homberg, W.; Trächtler, A.; Walther, F.: Microstructural investigation on phase transformation during flow forming of the metastable austenite AISI 304, in: Fortschritte in der Metallographie, 2020, G. Petow und F. Mücklich (Ed.), 2020.Search in Google Scholar
[4] Gorkunov, É.; Zadvorkin, S.; Mitropolskaya, Vichuzhanin, D. I.; Solov’ev, K.: Change in magnetic properties of metastable austenite steel due to elastoplastic deformation, Met. Sci. Heat Treat. 51, 9–10 (2009), pp. 423–428. DOI: 10.1007/s11041-010-9185-x10.1007/s11041-010-9185-xSearch in Google Scholar
[5] Schwartz, A.; Kumar, M.; Adams, B.; Field, D.: Electron backscatter diffraction in materials science, Springer US, Boston, MA, 2009. ISBN: 978148999334210.1007/978-0-387-88136-2Search in Google Scholar
[6] Wright, S.; Nowell, M.; Field, D.: A review of strain analysis using electron backscatter diffraction, Microsc. Microanal. 17, 3 (2011), pp. 316–329. DOI: 10.1017/S143192761100005510.1017/S1431927611000055Search in Google Scholar PubMed
[7] Vashista, M.; Moorthy, V.: Influence of applied magnetic field strength and frequency response of pick-up coil on the magnetic barkhausen noise profile, J. Magn. Magn. Mater. 345 (2013), pp. 208–214. DOI: 10.1016/j.jmmm.2013.06.03810.1016/j.jmmm.2013.06.038Search in Google Scholar
[8] Olson, G.; Cohen, M.: Kinetics of strain-induced martensitic nucleation, Metall Trans A 6A (1975), pp. 791–795. DOI: 10.1007/BF0267230110.1007/BF02672301Search in Google Scholar
[9] Nishiyama, Z.: Martensitic Transformation, Academic Press, Inc., New York, NY, USA, 1978. ISBN: 9780323148818Search in Google Scholar
[10] Mangonon, P.; Thomas, G.: The martensite phases in 304 stainless steel, Metall. Mater. Trans. 1 (1970), pp. 1577–1586.10.1007/BF02642003Search in Google Scholar
[11] Rafaja, D.; Ulrich, C.; Motylenko, M.; Martin, S.: Microstructure aspects of the deformation mechanisms in metastable austenitic steels, in: Austenitic TRIP/TWIP Steels and Steel-Zirconia Composites, H. Biermann and Ch. Aneiris (Ed.), Springer International Publishing, 2020. DOI: 10.1007/978-3-030-42603-3_1110.1007/978-3-030-42603-3_11Search in Google Scholar
[12] Weidner, A. (Hrsg.): Deformation processes in TRIP/TWIP steels, Springer International Publishing, 2020. ISBN: 978303037149410.1007/978-3-030-37149-4Search in Google Scholar
[13] Smaga, M.; Walther, F.; Eifler, D.: Investigation and modelling of theplasticity-induced martensite formation in metastable austenites, Int. J. Mater. Res. 97, 12 (2006), pp. 1648–1655. DOI: 10.3139/146.10139610.3139/146.101396Search in Google Scholar
© 2022 Walter de Gruyter GmbH, Berlin/Boston, Germany
Articles in the same Issue
- Contents
- Editorial
- Editorial
- Coupled microscopic and micromagnetic depth-specific analysis of plastic deformation and phase transformation of metastable austenitic steel AISI 304L by flow forming
- Segmented chip formation during machining under the influence of different atmospheres
- Lumen & Colours: A journey into the world of science
- Failure Analysis
- Cause analysis of the fluorescent displays on the guide vane platform
- Picture of the Month
- Picture of the Month
- News
- News
- Meeting Diary
- Meeting Diary
Articles in the same Issue
- Contents
- Editorial
- Editorial
- Coupled microscopic and micromagnetic depth-specific analysis of plastic deformation and phase transformation of metastable austenitic steel AISI 304L by flow forming
- Segmented chip formation during machining under the influence of different atmospheres
- Lumen & Colours: A journey into the world of science
- Failure Analysis
- Cause analysis of the fluorescent displays on the guide vane platform
- Picture of the Month
- Picture of the Month
- News
- News
- Meeting Diary
- Meeting Diary
