应力加速的金属玻璃老化动力学: 实验与原子模拟

Metallic glass (MG) is an amorphous alloy formed by rapid cooling, characterized by short-range order and unique physical and mechanical properties. Mechanical loading can lead to either overaging or rejuvenation. However, the physical mechanisms driving overaging under thermo-mechanical coupling remain poorly understood. This study focuses on the Zr₅₀Cu₄₀Al₁₀ MG, employing viscoelastic mechanical experiments and molecular dynamics simulations. It explores the evolution of relaxation time, mechanical properties, inherent structural potential energy, aging rate, and atomic activation energy under mechanical loading, aiming to elucidate the physical mechanisms underlying overaging. The findings indicate that during stress relaxation, the inherent structural potential energy decays more rapidly than under isothermal annealing. Applied stress decreases the atomic activation energy of the MG, supporting the notion that stress reduces the energy barriers for atomic rearrangements. Additionally, as temperature decreases and strain increases, the activation volume of the MG grows, suggesting that stress and temperature exert similar effects on local relaxation events. This study advances the understanding of stress relaxation processes and local relaxation events, offering theoretical guidance for producing super-stable glasses via mechanical loading.