MateriAlZ Seminar: Marie Charpagne

Abstract
With unmatched mechanical performance in harsh environments, polycrystalline metallic materials have been used in the energy and aerospace industry for decades. During service, they are subjected to cyclic mechanical loading, also called fatigue. The main avenue to designing more sustainable structural materials is through reaching a longer lifetime, hence better resistance to fatigue. This would allow to reduce maintenance, delay repair or part replacement, therefore preserving natural resources. Until now, most alloy design and microstructure optimization efforts have been targeted toward increasing the materials yield strength. Yet, as all metallic materials exhibit a trade-off between yield strength and fatigue strength, this implies that as we design stronger materials, their sustainability decreases.

Here, Dr. Charpagne will first present recent developments in the field of correlative microscopy, that have allowed to understand the fundamental mechanisms responsible for fatigue damage initiation: slip band formation - also called slip localization and slip irreversibility. Using an integrated experimental-numerical framework, she was able to map slip localization over large microstructure regions that are statistically representative of the materials and reveal its strong linkage with the materials microstructure.

Informed by these statistical measurements, Dr. Charpagne will then explore new microstructure design strategies aiming at minimizing the intensity of slip localization to overcome the yield strength/fatigue strength trade-off. Building-up on concurrent knowledge on microstructure development during manufacturing processes (recrystallization, grain growth and phase transformations), she will present several pathways to increase the fatigue performance in high-strength alloys through the examples of nickel-base superalloys and stainless steels. Finally, she will discuss the applicability of these strategies to additive manufactured materials.

Bio
Dr. Marie Charpagne obtained her Ph.D. in materials science at Mines ParisTech (2017) focusing on materials processing, after which she spent 4.5 years at UCSB as a postdoctoral researcher where she developed numerical tools for 3D correlative microscopy that couple microstructure with signatures of micro-plasticity. Started in Fall 2021, her group at UIUC designs sustainable, high-performance alloys with damage resistance and increased longevity. Using conventional processing pathways or additive manufacturing, they tailor materials from the micro-scale for improved mechanical and environmental resistance in harsh environments. She was awarded the Prize for the best Ph.D. thesis by the French Society for Materials and Metals (2017), was named a Rising Talent of the Women’s Forum for the Economy and Society (2017) and received an NSF-CAREER award in 2023. Aside from science, Marie is a classically trained concert pianist who has given over 50 recitals across Europe and the USA. She graduated from the conservatory of music with the highest honors and is a winner of several international piano competitions on several continents.