Understanding how materials respond under different loading conditions is crucial for designing the next generation of high strength steels. While the properties of metal alloys have long been linked to their microstructure, conventional characterization methods often fail to capture real-time microstructural evolution during deformation.
In his doctoral research, Lalit Pun addressed this challenge by utilizing high-energy X-rays from synchrotron sources to investigate strain-induced phase transformations in a metastable austenitic stainless steel. His research explores how strain rate, localized heating, and grain orientation influence the phase transformation from face centered cubic austenite to (near) body centered cubic martensite – a crucial transformation that enhances the mechanical performance of these steels.
In his research, Lalit Pun used a multi-scale approach, combining ex-situ, quasi in-situ, and fully in-situ tensile testing to capture both surface and bulk-level microstructural evolution.
"Traditional testing and characterization methods provide only a partial view of what happens inside a material during deformation. using in-situ synchrotron X-ray diffraction techniques, we can track microstructural changes in real-time, offering new insights into how these steels behave under different loading conditions," says Pun.
Lalit Pun conducted his doctoral research in Tampere University’s IMPACT - Multiscale Materials Testing Research Group. He currently works as a mechanical testing engineer at the UK Atomic Energy Authority, testing and developing materials for fusion applications.
Public defence on Friday 28 March
The doctoral dissertation of MSc Lalit Pun, titled The Role of Grain Orientation and Local Heating in the Strain-Induced Martensitic Transformation: In-situ and Ex-situ Studies will be publicly examined in the Faculty of Engineering and Natural Sciences at Tampere University at 12 o’clock on Friday 28 March 2025. The venue is at Hervanta campus in the auditorium K1702 of the Konetalo building, (Korkeakoulunkatu 6, Tampere).
The Opponents will be Assistant Professor Vahid Javaheri from University of Oulu and Doctor Sven Curtze from Thermo Fisher Scientific. The Custos will be Professor Mikko Hokka from the Faculty of Engineering and Natural Sciences.