In this article, we examine the unusual plastic deformation under uniaxial compression of an Al_2O_3-15 mol. Y_2O_3 (A15Y) glass synthesized by a wet chemical route. At a low temperature of 650-725 °C, plastic deformation of this glass is largely non-viscous through shear instabilities. In contrast, deformation near the crystallization temperature (850 °C) occurs homogeneously with work hardening and with a monotonic increase in the true density of the glass by 10-12, accompanied by an increase in hardness (H) and elastic modulus (E) of up to 100. We hypothesize a phenomenon of molecular densification of the amorphous structure through a hierarchy of multiple phases, analogous to density- or entropy-driven amorphous-to-amorphous phase transitions (polyamorphism). These results suggest that the present method of preparation and the unusual behavior can trigger a search for many more systems that display such behavior.
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机译：在本文中，我们研究了通过湿化学途径合成的 Al_2O_3-15 mol.% Y_2O_3 （A15Y） 玻璃在单轴压缩下的异常塑性变形。在 650-725 °C 的低温下，这种玻璃的塑性变形在很大程度上是非粘性的，因为剪切不稳定。相反，在结晶温度（850°C）附近发生变形时，加工硬化和玻璃真实密度单调增加10-12%，同时硬度（H）和弹性模量（E）增加高达100%。我们假设通过多相层次结构的分子致密化现象，类似于密度或熵驱动的无定形到无定形相变（多晶性）。这些结果表明，目前的制备方法和异常行为可以触发对更多显示这种行为的系统的搜索。
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