Abstract Activation-relaxation technique combined with molecular dynamics simulations was employed to investigate β-relaxation behavior in La55Ni20Al25 and Cu46Zr46Al8 model metallic glasses (MGs) for exploring the underlying mechanism. It is found that the activation energies are much smaller in La55Ni20Al25 MG, indicating that β-relaxation can be more easily activated in La55Ni20Al25 MG. It is also revealed that in both MGs, string-like diffusion dominates the atomic motions in β-relaxation. However, in different MGs, the string-like motions are found to involve atoms with different structure features, which could be the underlying structural basis of β-relaxation mechanism. In addition, because of very low activation energies, atomic hopping and cooperative rearrangements in La55Ni20Al25 MG also have significant impact on β-relaxation. However, such atomic motions are much weaker in Cu46Zr46Al8 MG, due to higher activation energies. These findings establish a physical link for activation energy and atomic motions in β-relaxation to atomic structures, and provide new understanding of β-relaxation mechanism in MGs.

中文翻译：

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La 55 Ni 20 Al 25 和Cu 46 Zr 46 Al 8 金属玻璃β-弛豫的活化-弛豫技术研究

摘要 采用活化-弛豫技术结合分子动力学模拟研究了La55Ni20Al25和Cu46Zr46Al8模型金属玻璃（MGs）的β-弛豫行为，以探索其潜在机制。发现 La55Ni20Al25 MG 的活化能要小得多，表明 La55Ni20Al25 MG 更容易激活 β-弛豫。还表明，在两种 MG 中，弦状扩散主导了 β-弛豫中的原子运动。然而，在不同的 MG 中，发现弦状运动涉及具有不同结构特征的原子，这可能是 β-弛豫机制的潜在结构基础。此外，由于非常低的活化能，La55Ni20Al25 MG 中的原子跳跃和协同重排也对 β-弛豫有显着影响。然而，由于较高的活化能，这种原子运动在 Cu46Zr46Al8 MG 中要弱得多。这些发现为β-弛豫中的活化能和原子运动与原子结构建立了物理联系，并为MGs中的β-弛豫机制提供了新的理解。