Compact A15 Frank-Kasper nano-phases at the origin of dislocation loops in face-centred cubic metals

• Published in: Nature communications 2023-12, Vol.14 (1)
• Main Authors: Goryaeva, Alexandra, Domain, Christophe, Chartier, Alain, Dézaphie, Alexandre, Swinburne, Thomas, Ma, Kan, Loyer-Prost, Marie, Creuze, Jérôme, Marinica, Mihai-Cosmin
• Format: Article
• Language: English
• Subjects: Physics
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-38729-6

Abstract It is generally considered that the elementary building blocks of defects in face-centred cubic (fcc) metals, e.g., interstitial dumbbells, coalesce directly into ever larger 2D dislocation loops, implying a continuous coarsening process. Here, we reveal that, prior to the formation of dislocation loops, interstitial atoms in fcc metals cluster into compact 3D inclusions of A15 Frank-Kasper phase. After reaching the critical size, A15 nano-phase inclusions act as a source of prismatic or faulted dislocation loops, dependent on the energy landscape of the host material. Using cutting-edge atomistic simulations we demonstrate this scenario in Al, Cu, and Ni. Our results explain the enigmatic 3D cluster structures observed in experiments combining diffuse X-ray scattering and resistivity recovery. Formation of compact nano-phase inclusions in fcc structure, along with previous observations in bcc structure, suggests that the fundamental mechanisms of interstitial defect formation are more complex than historically assumed and require a general revision. Interstitial-mediated formation of compact 3D precipitates can be a generic phenomenon, which should be further explored in systems with different crystallographic lattices.