Cu-Zr非晶合金薄带的高温拉伸蠕变研究

Tensile Creep Behaviors of Cu-Zr Metallic Glass Ribbons at High Temperature

中文关键词: Cu-Zr非晶合金薄带 高温拉伸蠕变 激活能 应力指数

英文关键词: Cu-Zr metallic glass ribbons, high temperature tensile creep, activation energy, stress exponent

中文摘要:

      以经典的二元非晶合金Cu₅₀Zr₅₀和Cu₆₀Zr₄₀薄带为研究对象,通过动态力学分析仪(DMA)系统研究应力和温度对其接近玻璃转变温度(T_g)下的单轴拉伸蠕变性能的影响。在相同升温速率下分别采用差式扫描热分析与动态力学分析测得其玻璃转变温度。利用阿伦尼乌斯关系得到Cu₅₀Zr₅₀和Cu₆₀Zr₄₀非晶带材蠕变表观激活能分别为5.3 eV和6.2 eV,表明Cu-Zr非晶合金的拉伸蠕变变形与玻璃转变(α弛豫)相关。计算出蠕变应力指数n,发现n随着温度的升高而减小,最终接近1,表明Cu₅₀Zr₅₀和Cu₆₀Zr₄₀非晶在接近玻璃转变温度时蠕变变形趋向于牛顿粘性流动。

英文摘要:

      The typical Cu₅₀Zr₅₀ and Cu₆₀Zr₄₀ binary metallic glasses ribbons were taken as object of this study, the effects of stress and temperature on uniaxial tensile creep at temperature close to the Tg (glass transition temperature) were studied systematically via dynamic mechanical analyzer (DMA). The T_g was measured by differential scanning calorimeter (DSC) and DMA at the same heating rate, respectively. The apparent activation energies for the creep of Cu₅₀Zr₅₀ and Cu₆₀Zr₄₀ were obtained from Arrhenius equation, which were 5.3 eV and 6.2 eV, respectively. This indicates that the tensile creep deformation of Cu-Zr metallic glasses is related to the glass transition (α-relaxation) behavior. Further calculation showed that creep stress exponent (n) decreasesd with the increasing temperature and was finally close to 1, which demonstrated Cu₅₀Zr₅₀ and Cu₆₀Zr₄₀ metallic glasses tend to be Newtonian viscous flow when they approach to glass transition stage.