Intriguing Deformation Transition Behavior of Lithium Disilicate Crystal

We report an intriguing anisotropic deformation behavior of lithium disilicate crystal under tensile loadings via molecular dynamics simulations. The crystal undergoes clear brittle cleavage in the [010] direction, while exhibiting a first-order transition with the critical stress of around 8 GPa in the [100] direction. The transition is exclusively facilitated by local Li-O bond breakage spreading to the whole sample. This hierarchical deformation mechanism enables overall structure integrity while undergoing large degrees of deformation. To the best of our knowledge, this is the first observation on this intriguing deformation behavior that might inspire new designs of tougher lithium disilicate glass-ceramics.