中文摘要：

近年来，基于非晶合金名义弹性区的流变力学行为探索其结构及形变机理是非晶合金领域研究的热点之一．本文根据非晶合金结构不均匀性的特征，提出能够比拟树状分形网络结构的分数阶微分流变模型研究非晶合金的黏弹性行为．通过室温纳米压痕实验，对三种不同泊松比和玻璃化转变温度的非晶合金的黏弹性变形行为进行了研究．实验结果表明：在表观弹性区，非晶合金的变形表现出与加载速率相关的线性黏弹性性质．根据Riemann-Liouville分数阶微积分定义，分别由分数阶微分及整数阶Kelvin模型对实验结果进行了分析．分析结果表明：相对于整数阶流变模型，分数阶微分流变模型能更精细地表征材料的黏弹性变形特征；在流变模型参数中，黏性系数ηA和分数阶次α反映出材料的流变特性和流动趋势，流变参数与玻璃转变温度、泊松比之间具有较好的相关性，上述相关性有助于从微观结构角度理解材料塑性与泊松比的关联．

英文摘要：

Metallic glasses offer novel physical, chemical and mechanical properties and have promising potential applications. Recently, exploring the structure and deformation mechanism of metallic glasses according to the rheological mechanical behavior in the nominal elastic region has been the object of intensive research. Physically the mechanical analogues of fractional elements can be represented by self-similarity spring-dashpot fractal networks. In light of the fractal distri- bution features of the structural heterogeneities, a fractional differential rheological model is introduced to explore the viscoelastic a behavior of metallic glasses in this paper. To investigate the viscoelastic deformation mechanism, carefully designed nanoindentation tests at ambient temperature are proposed in this study. Three kinds of metallic glasses with different Poisson＇s ratio and glass transition temperature, which have the chemical compositions of Pd40Cu30Ni10P20, Zr48Cu34Pd2A1sAgs, and （Fe0.432Co0.288B0.192Si0.04sNb0.04）96Cr4 are selected as the model materials. Experimental and theoretical results clearly indicate that in the nominal elastic region, these metallic glasses exhibit linear viscoelasticity, implying a loading rate-dependent character. Based on the fractional calculus and Riemann-Liouville definition, ex- perimental results are analyzed by the fractional-differential and integer order rheology models respectively. According to the stability of the fitting parameters, here we show that the fractional-differential Kelvin model, which consists of a spring and a fractional dashpot element, can fit the experimental viscoelastic deformation data of the investigated metallic glasses better than that with integer order rheological model. The extracted elastic modulis E1 of the spring in the fractional-differential Kelvin model are comparable to those of samples measured by traditional methods. Such a similarity can be well explained by the mechanical analogue of fractal model proposed for describing the distributio