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MM: Fachverband Metall- und Materialphysik

MM 18: Liquid and Amorphous Materials II

MM 18.4: Vortrag

Dienstag, 10. März 2026, 14:45–15:00, SCH/A315

A ReaxFF study of the covalency-driven cracking-to-shearing transition in metal-metalloid glasses — •Shansi Liao¹, Jürgen Eckert^1,2, and Daniel Sopu^1,3 — ¹Erich Schmid Institute of Materials Science, Leoben, Austria — ²Technical University of Leoben,Leoben, Austria — ³Technical University of Darmstadt, Darmstadt, Germany

Revealing the atomistic origins of failure in amorphous solids remains challenging. In metal-metalloid glasses, mechanical response is strongly governed by the breaking and reformation of covalent bonds which cannot be adequately captured by non-reactive interatomic potentials. Here, large-scale reactive molecular dynamics simulations using a ReaxFF potential that includes angular constraints for covalent bonding reveal a composition-dependent transition from cleavage cracking to shear banding in model CuSi glasses. During loading, a highly connected, rigid Si-rich network suppresses strain delocalization, generating mechanically unstable regions characterized by shear-induced reductions in coordination number and severe distortions of Si-Si-Si bond angles. These unstable regions serve as energetically favorable pathways along which the crack advances. As Cu content increases, reduced angular rigidity promotes widespread shear transformation and shear-band-mediated plasticity. In contrast, the modified embedded-atom method potential, which intrinsically overestimates the angular flexibility of the Si-rich networks, fails to reproduce this transition. Our results show that angular rigidity of the interatomic potential is a key descriptor of plasticity in metal-metalloid glasses.

Keywords: Metal-metalloid glass; Molecular dynamics; Shear bands; Cracking; Mechanical properties