Effect of TCP phases on tensile properties of engineering alloys: Insights gained from a CrMnFeCoNi high-entropy alloy (31/10/25)
Speaker and Affliation:
Dr. Aditya Srinivasan Tirunilai
Post Doctoral Researcher, Ruhr-University Bochum
When?
31st October, 2025 (Friday), 4.00 PM (India Standard Time)
Where
KI Vasu Auditorium, Dept. of Materials Engineering, IISc, Bangalore
Abstract:
Topologically closed-packed (TCP) phases are complex intermetallic phases that often precipitate in and can significantly influence the mechanical behavior of a wide range of engineering alloys, ranging from superalloys and steels to high-entropy alloys (HEAs). While certain effects of TCP phases have been reported in the past, generally in terms of strengthening or embrittling, other vital aspects are usually ignored, namely matrix compositional change, associated temperature-intrinsic property variation, particle damage accumulation, etc. More importantly, the evaluation of strength or ductility itself is generally not carried out in a quantitatively transferable way. In the present talk, our recent efforts to disentangle multiple, often competing effects in mechanical behavior, originating from a TCP phase, will be presented. A model HEA composition from the CrMnFeCoNi system, with a consistent initial microstructure, is used to determine the effects of a TCP phase (presently the σ-phase). This will be described through the interaction between precipitates and the matrix, their impact on strength and work-hardening, and how these differ at different temperatures, as evaluated through tensile testing. The result offer insights into the interplay between TCP content, solute depletion, intrinsic strength, twinning ability, to name a few. Based on the rigor and the relatively large number of mechanical tests, we consider this to be the first view on quantitatively transferrable evaluation of TCP phase in a structural alloy.
Speaker Bio:
Aditya Srinivasan Tirunilai is currently a postdoctoral researcher at Ruhr-University Bochum(RUB), in the Chair for Materials Science and Engineering, working with Prof. Guillaume Laplanche in the Microstructure of Materials group. He received the Walter Benjamin fellowship for his position in RUB. Aditya earned his Doctorate in 2021 from the Institute of Applied Materials at the Karlsruhe Institute of Technology, where he worked in the Physical Metallurgy group, led by Prof. Martin Heilmaier. Aditya completed his Master of Technology at the Indian Institute of Technology Madras in 2017.