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MM: Fachverband Metall- und Materialphysik

MM 45: Mechanical Properties and Alloy Design: e.g. Light-Weight, High-Temperature, Multicomponent Materials IV

MM 45.3: Talk

Wednesday, March 20, 2024, 16:15–16:30, C 230

Anomalous brittleness of iridium: Atomistic insights from DFT and ACE simulations — •Minaam Qamar, Matous Mrovec, Yury Lysogorskiy, and Ralf Drautz — ICAMS, Ruhr University Bochum, Germany

The anomalous brittle nature of face-centered cubic (fcc) metal iridium has puzzled researchers for decades. We investigated fracture mechanisms in Ir using atomistic simulations based on density functional theory (DFT) and the atomic cluster expansion (ACE). ACE is a data-driven interatomic potential with a formally complete basis that can reach quantum accuracy while remaining highly computationally efficient. Both transgranular cleavage in perfect bulk and intergranular fracture along grain boundaries were examined. Detailed computational tensile tests for several grain boundaries were performed in parallel for Ir and Cu, which can be considered a prototypical ductile fcc metal. Subsequently, ACE parametrizations for both metals were employed in large-scale atomistic simulations of various fracture scenarios at finite temperatures and different loading conditions. We will present results of the simulations and discuss new insights into the intrinsic fracture behavior of Ir.

Keywords: Iridium; brittle; ACE; transgranular; intergranular