【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。更多还原

【Abstract】 The β-relaxation is the principal source of the dynamics in glassy state, but its structural origin is still not well understood. In the present paper, the correlation between the β-relaxation and mixing enthalpy was studied, and the chemical effect was interpreted from the aspect of local structure. The dynamic mechanical measurements and molecular dynamics simulation were performed for Zr-Cu and Zr-Ni metallic glasses. Results indicate 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.更多还原