NOMATEN ONLINE-SEMINAR February 20: Efficient discovery of ultra-strong high-entropy alloys by mechanistic theory of yield strength
NOMATEN ONLINE-SEMINAR
online: https://meet.goto.com/NCBJmeetings/nomaten-seminar
Tuesday, FEBRUARY 20th 2024 13:00 CET
Efficient discovery of ultra-strong high-entropy alloys by mechanistic theory of yield strength
Dr. Francesco Maresca
Engineering and Technology Institute Groningen, Faculty of Science and Engineering, University of Groningen, 9747 AG Groningen, The Netherlands
Abstract:
Body-centered-cubic (BCC) high entropy alloys show exceptional strengths up to 1900K [1]. Fundamental understanding of the mechanisms that control strengthening is necessary to formulate a theory that enables screening over the immense compositional HEA space [2]. Supported by experimental findings in NbTaTiV and CrMoNbV alloys [3], we show with theory [4] that edge dislocations can control the yield strength in BCC high entropy alloys [3]. The theory of edge dislocation strengthening is based on the interaction of the edge dislocations with the random field of solutes in the HEAs. The theory rationalizes and captures a broad range of experiments on BCC alloys. The theory is cast in an analytical form that is parameter-free and depends on physical quantities (alloy concentrations, lattice parameter, elastic constants, misfit volumes) that can be determined ab-initio or experimentally. The reduced theory enables screening over 10 million compositions in the whole Al-Cr-Mo-Nb-Ta-W-V-Ti-Zr-Hf alloy family to find the strongest BCC HEAs.
References:
[1] O.N. Senkov, G.B. Wilks, J.M. Scott, D.B. Miracle (2011) Mechanical properties of Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 refractory high entropy alloys, Intermetallics 19, 698-706.
[2] B. Cantor (2014) Multicomponent and High Entropy Alloys, Entropy 16, 4749-4768.
[3] C. Lee, F. Maresca et al., Strength can be controlled by edge dislocations in refractory high-entropy alloys, Nature Communications 12:5474, 2021.
[4] F. Maresca and W.A. Curtin, Mechanistic origin of high strength in refractory BCC high entropy alloys up to 1900K, 182:235–249, 2020
Bio:
Dr. Francesco Maresca is Assistant Professor at the Engineering and Technology Institute (ENTEG) at the University of Groningen (Netherlands). He received his Ph.D. "cum laude" in Mechanical Engineering (Mechanics of Materials) at the Eindhoven University of Technology (TU/e) with advisors Prof. Marc Geers and Dr. Varvara Kouznetsova, working on a thesis about plasticity of martensite in low-alloyed steels. His thesis received multiple awards in the Netherlands, as well as abroad as the best PhD thesis in Europe in the field of metallurgy and materials science of steels (granted by Stahlinstitut VDEh Düsseldorf). After a postdoctoral research period at EPFL where he started his research on High Entropy Alloys together with his advisor Prof. Bill Curtin, he started his own research group (Multi-Scale Mechanics, MSM) at the University of Groningen. His current focus is on the atomistic (Molecular Dynamics) and micromechanics (Crystal Plasticity) modelling of plasticity, twinning and fracture, including application of machine learning techniques, for High Entropy Alloys, Hydrogen Embrittlement, Liquid Metal Embrittlement and Shape Memory Alloys.
