Zr-Cu和Zr-Ni金属玻璃中混合焓对β弛豫的影响

The effect of mixing enthalpy on the β-relaxation in Zr-Cu and Zr-Ni metallic glasses

摘要:

β弛豫是金属玻璃中重要的动力学过程，但是β弛豫的结构起源尚不清楚。本文研究了β弛豫与混合焓的关联性，并从局域结构的角度对这种关联性进行了解释。针对Zr-Cu和Zr-Ni金属玻璃，进行了动态力学分析和分子动力学模拟，结果表明较大负值的混合焓有利于体系中二十面体团簇的形成，而这种具有较高动力学稳定性的二十面体团簇对β弛豫过程中的原子运动具有一定的抑制作用。

Abstract:

The β-relaxation is the principal source of the dynamics in glassy state, but the structural origin of β-relaxation is still not well understood. Here, the correlation between the β-relaxation and mixing enthalpy was studied, and the chemical effect is interpreted from the aspect of local structure. The dynamic mechanical measurements and molecular dynamics simulation of local structure were performed for Zr-Cu and Zr-Ni metallic glasses, which indicates the smaller negative mixing enthalpy facilitates the formation of the icosahedral clusters, and atom motion related to the β-relaxation is hindered by icosahedral clusters with high dynamic stability.