Oxide glasses are an integral part of the modern world, but their usefulness can be limited by their characteristic brittleness at room temperature. As an exception to the rule, amorphous aluminum oxide (a-Al₂O₃) is a rare diatomic glassy material exhibiting significant nanoscale plasticity at room temperature [1]. Here we show experimentally that the room temperature plasticity of a-Al₂O₃ extends to microscale and high strain rates using in situ micropillar compression. All tested a-Al₂O₃ micropillars with diameters ranging between 2 - 11 um deform without fracture, up to 50 % strain, via a combined mechanism of viscous creep and shear band slip propagation. Large-scale molecular dynamic simulations and finite elements simulations align with the main experimental observations and verify the plasticity mechanisms at the atomic scale and mesoscale. The experimental strain rates are expanded to an order of magnitude observed in typical impact loading scenarios, such as hammer forging, with strain rates up to the order of 1 000 s^-1, and we expand the total a-Al₂O₃ sample volume exhibiting significant low temperature plasticity without fracture by 5 orders of magnitude from previous observations. Current discovery is consistent with the theoretical prediction that the plasticity mechanism observed in a-Al₂O₃ can extend to macroscopic bulk glasses if material is free of processing flaws and suggests that amorphous oxides show significant potential to be used as light, high-strength, and damage-tolerant engineering materials. Results also indicate that it is feasible to experimentally produce such flaw free samples at a bulkier scale.
 
[1]  Frankberg et al. Science 2019, 366:6467, 864-869