Speaker and Affliation:
Dr. Heena Khanchandani
Institute for General Materials Properties, Department of Materials Science,
Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen 91058, Germany
02nd November, 2023 (Thurssday), 3.00 PM (India Standard Time)
K I Vasu Auditorium, Dept. of Materials Engineering, IISc, Bangalore
Heena Khanchandani is currently working as a post-doctoral research scientist with Prof. Peter Felfer in the Department of Materials Science and Engineering at Friedrich-Alexander- University in Erlangen, Germany since October 2022. She is working on investigating the hydrogen embrittlement susceptibility of carbon austenitic steels. She graduated with a PhD in August 2022 from the Max-Planck-Institute for Iron Research in Dusseldorf, Germany where she worked in the Atom Probe Tomography group with Prof. Baptiste Gault. Her PhD thesis was based on examining the hydrogen embrittlement mechanisms in a high-manganese twinning induced plasticity steel by using correlative electron microscopy and atom probe tomography. She has a Masters degree in Materials Science through Erasmus Mundus Masters programme, thereby receiving joint Masters degree from two institutions: University of Montpellier, France and Ludwig Maximilians University Munich, Germany. She studied Bachelor of Technology in Metallurgical and Materials Engineering at Malaviya National Institute of Technology Jaipur, India.
High-manganese austenitic twinning induced plasticity (TWIP) steels exhibit high strain hardening, high tensile strength and ductility, which make them promising materials for automotive and structural applications . However, they are susceptible to oxidation  and hydrogen embrittlement (HE) during service loading conditions . We investigated the influence of hydrogen on the dislocation structure in a model Fe-27Mn-0.3C (wt.%) TWIP steel. We observed the microstructural evolution from the formation of dislocation cells at 3% tensile strain to the formation of stacking faults at 7% tensile strain due to the presence of hydrogen. The associated deformation mechanisms will be discussed during the talk. We also investigated the mechanisms underpinning the oxidation and HE by atom probe tomography where we measured the segregation of hydrogen and oxygen at grain boundaries. We studied the role of carbon and manganese in the oxidation and HE susceptibility which are major alloying elements in TWIP steels. This study motivated the design of a carbon austenitic steel which has higher resistance to HE. The results on TWIP steel and the carbon austenitic steel will be presented in details during this presentation. References  B.C. De Cooman, O. Kwon, K.G. Chin, Mater. Sci. Technol. 28 (2012) 513–527.  D.M. Bastidas, J. Ress, J. Bosch, U. Martin, Metals (Basel). 11 (2021) 1–45.  M. Koyama, E. Akiyama, K. Tsuzaki, Scr. Mater. 66 (2012) 947–950.