Fast dynamics in a model metallic glass-forming material

We investigate the fast β- and Johari–Goldstein (JG) β-relaxation processes, along with elastic scattering response of glass-forming (GF) liquids boson peak, in a simulated Al–Sm GF material exhibiting fragile–strong (FS) transition. These dynamical processes are universal “ordinary” fluids collectively describe their “fast dynamics,” we find these relaxation also arise liquid FS String-like particle motion, having both an irreversible reversible nature (stringlets) component, occurs fast-dynamics regime, corresponding to ps timescale. collective motion associated localized unstable modes facilitates intermittent “jumping” events at long times JG process, while stringlets stable perfectly atomic give rise peak. To further clarify origin calculate density states for stringlet particles “normal” that normal atoms do not. The growth upon heating ultimately leads “softening” excitations, peak frequency shear modulus drop concert this softening. string-like regime is shown be responsible intensity process. Relaxation cooled clearly involves hierarchy acting on rather different timescales spatial scales.