A wine glass breaks when it falls from hand or is hammered. But when a metallic object (say, a container) is hammered, it only deforms without breaking. Why? Is it somehow related to the fact that glass is amorphous while metal is not?
at room temperature, there are nanoscale deformation mechanisms available to most metals which allow them to withstand plastic flow without fracture. these deformation mechanisms (primarily dislocation glide and climb) are absent in glasses, which tend instead to shatter when stressed in tension.