Micro-mechanisms of deformation and failure in advanced high strength steels unraveled through full-field strain mapping

Date: Jul 12, 2023
Time: 11:00 AM - 12:00 PM (Local Time Germany)
Speaker: Associate Professor Nagamani Jaya Balila
Associate Professor in the Department of Metallurgical Engineering and Materials Science Indian Institute of InTechnology Bombay
Location: Max-Planck-Institut für Eisenforschung GmbH
Room: Large Conference Room No. 203
Host: on invitation of Prof. Gerhard Dehm

Advanced high strength steels are typically complex, multi-phase materials, which allow for thermo-mechanical designing of microstructures tailored to required strength-ductility combinations. In this talk, I cover two specific cases: maraging steel used in rocket motor casings, a martensitic, precipitation strengthened Fe-Ni steel; and dual-phase automotive steel, a ferrite-martensite Fe-low C steel, where we unravel the micromechanisms of strain accommodation and onset of damage nucleation [1-6]. This is in turn used to engineer microstructures with better fracture resistance. In-situ optical or SEM based digital image correlation is used for mapping the strain fields in these materials to identify strain partitioning characteristics in a high throughput manner. Finally, triaxial stress states are explored through novel miniature tests to determine failure mechanisms in service loading conditions.

References:

1. S. Basu, B. Nagamani Jaya, "Correlative Characterization and Plasticity Modeling of Microscopic Strain Localizations in a Dual Phase Steel", Materials Characterization, Vol 197, 2023, 112704

2. K. Jacob, H. Sahasrabuddhe, A. Hohenwarter, S. Dixit, B. Nagamani Jaya, “Micro-mechanisms of failure in nano-structured maraging steels characterised through in-situ mechanical tests”, Nanotechnology, Vol 34, No 2, 2023, 025703

3. Soudip Basu, Anirban Patra, B. Nagamani Jaya, Sarbari Ganguly, Monojit Dutta, Indradev Samajdar “Study of microstructure-property correlations in dual phase steels for achieving enhanced strength and reduced strain partitioning”, Materialia, Vol 25, 2022, 101522

4. K. Jacob, A. Roy, M. P. Gururajan, B. Nagamani Jaya, “Effect of dislocation networks on precipitate morphology in maraging steels” Materialia, Vol 21, 2022, 101358.

5. S. Basu, B. Nagamani Jaya, A. Patra, S. Ganguly, M. Dutta, A. Hohenwarter, I. Samajdar, “The Role of Phase Hardness Differential on the Non-Uniform Elongation of a Ferrite-Martensite Dual Phase steel” Metallurgical and Materials Transactions A, Vol 52, 2021, 4018

6. K. Jacob, D. Yadav, S. Dixit, A. Hohenwarter, B. Nagamani Jaya, “High Pressure Torsion Processing of Maraging Steel 250: Microstructure and Mechanical Behaviour Evolution” Materials Science and Engg A, Vol 802, 2021, 140665