通过高分辨率X射线散射揭示玻璃在压痕过程中的变形机制
Uncovering the deformation mechanism of glasses during indentation through high-resolution X-ray scattering
浏览论文内容
中文总结 AI 辅助
本研究利用同步辐射X射线纳米散射原位表征压痕过程中玻璃的亚表面变形机制，发现氧化物玻璃变形区特征随泊松比变化，为耐损伤玻璃设计提供了新依据。
中文摘要 AI 辅助
压痕实验可用于模拟玻璃的实际损伤事件，这类损伤会导致表面缺陷，进而降低玻璃的实际强度。传统压痕研究往往关注卸载后的表面变形，但要理解表面变形与结构之间的关联，关键在于表征压痕过程中的亚表面变形。压痕诱导的变形包含弹性区和塑性区，其受玻璃成分与结构、压痕及大气条件、应力状态的调控。然而，目前仅有少数实验方法可用于表征压痕过程中亚表面的压痕变形机制。本研究采用同步辐射X射线纳米散射技术，在四种具有不同结构特征的氧化物玻璃和氧氮化物玻璃的压痕过程中原位探测其变形机制，具体通过高空间分辨率（低至约100 nm）测量X射线结构因子的第一尖锐衍射峰的位置和强度变化来实现。研究发现，这些玻璃的变形区（其特征为不同压痕载荷下致密化与剪切流动的形状、尺寸及相对贡献）随泊松比变化。因此，本研究为氧化物玻璃的力学行为提供了新的见解，有助于设计更耐损伤的玻璃。
英文摘要
Indentation experiments can be used to mimic real-life damage events of glasses that lead to surface flaws and thus lower practical strength. Conventional indentation studies often focus on the surface deformation after unloading. However, to understand the link between the surface deformation and structure, it is crucial to characterize the sub-surface deformation during the indentation process. The indentation-induced deformation, consisting of both elastic and plastic zones, is governed by the glass composition and structure, indentation and atmospheric conditions, and stress state. However, only a few experimental methods exist for characterizing the sub-surface indentation deformation mechanism during indentation. In this study, we use synchrotron X-ray nanoscattering to probe the deformation mechanism in situ during indentation of four types of oxide and oxynitride glasses with distinct structural features. This is done by measuring the variation in the position and intensity of the first sharp diffraction peak of the X-ray structure factor with a high spatial resolution down to ~100 nm. We find that the deformation zones of these glasses, which are characterized by the shape, size, and relative contribution between densification and shear flow under different indentation loads, vary with Poisson's ratio. Thus, our work provides new insights into the mechanical behavior of oxide glasses, contributing to the design of more damage-resistant glasses.
