The sample size effect on deformation mode of glasses is one of the most misunderstood properties of this class of material. This effect is intriguing, since materials deemed macroscopically brittle become plastic at small size. We propose an explanation of this phenomenon for metallic glasses. A thermodynamic description of the local rearrangement zones activated under an applied stress is proposed. Using the Poisson distribution to describe the statistics of these zones and the statistical physics to associate entropy, we define a critical sample size for the change in the deformation mode. Predictions are in agreement with experimental observations and reveal hidden structural parameters describing the glassy state.

样品尺寸对玻璃变形模式的影响是此类材料中最容易被误解的特性之一。这种效果令人着迷，因为宏观上被认为是脆性的材料会以小尺寸变成塑料。我们提出一种解释这种现象的金属玻璃。提出了在施加应力下激活的局部重排区的热力学描述。使用泊松分布来描述这些区域的统计信息以及用于关联熵的统计物理学，我们为变形模式的变化定义了一个临界样本大小。预测与实验观察一致，并揭示了描述玻璃态的隐藏结构参数。