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The authors recently reported that undercooled liquid Ag and Ag–Cu alloys both exhibit a first order phase transition from the homogeneous liquid (L-phase) to a heterogeneous solid-like G-phase under isothermal evolution. Here, we report a similar L–G transition and heterogenous G-phase in simulations of liquid Cu–Zr bulk glass. The thermodynamic description and kinetic features (viscosity) of the L-G-phase transition in Cu–Zr simulations suggest it corresponds to experimentally reported liquid–liquid phase transitions in Vitreloy 1 (Vit1) and other Cu–Zr-bearing bulk glass forming alloys. The Cu–Zr G-phase has icosahedrally ordered cores versus fcc/hcp core structures in Ag and Ag–Cu with a notably smaller heterogeneity length scale Λ . We propose the L–G transition is a phenomenon in metallic liquids associated with the emergence of elastic rigidity. The heterogeneous core–shell nano-composite structure likely results from accommodating strain mismatch of stiff core regions by more compliant intervening liquid-like medium. 

Abstract The shear‐induced amorphization has been observed in many strong ceramics and is responsible for their cracking and fragmentation. But its underlying mechanism remains elusive due to the complex structure and bonding environment in strong ceramics. To illustrate the deformation mechanism of local amorphization in strong ceramics, we employed molecular dynamics simulations with a deep‐learning force field to examine the shear‐induced amorphization in B₁₂P₂. Surprisingly, we identified a stacking‐fault‐mediated amorphization mechanism along the most plausible slip system (1 1 1)/[1 1 ]. This mechanism is even more favorable at a higher temperature than room temperature. In contrast, the direct crystal to amorphization transition, due to the icosahedral slip, is observed for the other most plausible slip system (0 1 1)/[2 ]. We report the activation volume and the activation free energy for the amorphization along the (1 1 1)/[1 1 ] slip system. The derived activation volume is only 41.47 A³, which is roughly 2–3 icosahedra, suggesting that the localized amorphization in B₁₂P₂is mediated by stacking fault formation. The previous results suggest complex amorphization mechanisms in strong ceramics.