Reaching the Yield Point of a Glass During X-Ray Irradiation - Giulio Monaco (Department of Physics and Astronomy, University of Padua)

A solid loaded beyond the yield stress loses its elastic properties and becomes plas-
tic. From a microscopic point of view, this limit corresponds to the condition where
plastic regions become so densely packed that they give rise to system-spanning
structures. This limit for glasses is abrupt, which makes experimental investigations
challenging. Here [1], the yield point is reached by the alternative approach of in-
creasing the density of plastic regions by generation of point defects during x-ray
irradiation. For the case of a LiBO2 glass, we show that at low doses, i.e., for a low
density of defects, the defects behave as isolated stress sources that induce atomic
displacements typical of an elastic solid. As the density of defects increases, the me-
chanical response of the glass at the local scale changes from elastic to more and
more plastic, until reaching the limit where it becomes characteristic of a flowing sys-
tem, which signals that the yield point is reached.

[1] A. Martinelli et al., Phys. Rev. X 13, 041031 (2023).

Contact: Kirsten Martens