Dynamic glass transition in Zr-Al-Ni-Cu bulk metallic glass
Dynamic glass transition in Zr-Al-Ni-Cu bulk metallic glass
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DOI：
10.1016/j.msea.2006.02.218
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发表时间：
2006-12
期刊：
影响因子：
6.4
通讯作者：
M. Hojo;H. Numakura
中科院分区：
文献类型：
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作者：
M. Hojo;H. Numakura
采用等温强迫振动法研究了Zr_（55）Al_（10）Ni_（55）Cu_（30）大块非晶合金的弹性和粘弹性行为。在量热玻璃化转变的温度下，在恒定温度下将频率从10+ 1降低到10− 3 Hz时，储能模量表现出一个数量级的显著下降，这与连续加热下观察到的变化相似。储能模量的降低和伴随的损耗模量的最大值表明动态玻璃化转变;材料在高频率下表现为固体，但在低频率下表现为液体。储能模量和损耗模量表现出特征行为的频率范围比从简单的麦克斯韦粘弹性模型所预期的要宽得多。一个平行的组合的麦克斯韦单位被发现重现所观察到的趋势，并被用来评估的特征速率常数。其活化能和指前因子都很高，表明动态玻璃化转变是由原子的集体运动控制的。
The elastic and viscoelastic behavior of a bulk metallic glass Zr55Al10Ni5Cu30(in mol%) has been studied by isothermal forced-vibration measurements of the dynamic shear modulus. At temperatures of the calorimetric glass transition, on decreasing the frequency from 10+1to 10−3Hz at a constant temperature, the storage modulus exhibits a striking drop, of an order of magnitude, which is similar to the change observed under continuous heating. The lowering of the storage modulus and the accompanying maximum in the loss modulus indicate a dynamic glass transition; the material behaves as a solid at high frequencies but as a liquid at low frequencies. The range of frequencies where the storage and loss moduli exhibit the characteristic behavior is much wider than expected from a simple Maxwell model of viscoelasticity. A parallel combination of Maxwell units is found to reproduce the observed trend, and is used to evaluate the characteristic rate constant. Its activation energy and the pre-exponential factor turn out to be anomalously high, indicating that the dynamic glass transition is controlled by collective movements of atoms.