Threshold damage mechanisms in brittle solids and their impact on advanced technologies

Chipping of ceramic‐based dental materials by micrometric particles

“…Indeed, although particles are not necessarily harder than the crown material, they often contain sharp edges that greatly intensify the contact stress field 21,22 . The local damage that they produce, even at low (subthreshold) loads, decreases the strength of the material 23 and accelerates the long‐term mechanical degradation in the form of wear 20,24–26 …”

“…Although such small-scale events would not be immediately catastrophic because the size of the chip is micrometric, they pose a threat to the structural integrity by degrading the fracture strength to a significantly greater extent than subthreshold microcontacts. 23 Dislodged chips containing sharp edges can in turn cause secondary chipping and wear. Furthermore, the attendant increase in surface roughness is likely to result in a very aggressive wear of the opposing dentition (antagonist wear).…”

“…One phenomenon that has been less studied in dental materials is the occurrence of chipping damage induced by sharp, micrometric particles, that is, not macroscopic chipping events from tooth–tooth contacts but rather chipping at the microcontact/particle level. Although such small‐scale events would not be immediately catastrophic because the size of the chip is micrometric, they pose a threat to the structural integrity by degrading the fracture strength to a significantly greater extent than subthreshold microcontacts 23 . Dislodged chips containing sharp edges can in turn cause secondary chipping and wear.…”

“…Indeed, although particles are not necessarily harder than the crown material, they often contain sharp edges that greatly intensify the contact stress field. 21,22 The local damage that they produce, even at low (subthreshold) loads, decreases the strength of the material 23 and accelerates the long-term mechanical degradation in the form of wear. 20,[24][25][26] One phenomenon that has been less studied in dental materials is the occurrence of chipping damage induced by sharp, micrometric particles, that is, not macroscopic chipping events from tooth-tooth contacts but rather chipping at the microcontact/particle level.…”

Superior Room Temperature Compressive Plasticity of Submicron Beta‐Phase Gallium Oxide Single Crystals

“…[23][24][25][26] Deformation of brittle solids may also transit from brittle to ductile during room temperature indenting/scratching/cutting once the characteristic contact dimension is reduced below a critical value. [27,28] Sizeeffected plasticity has been recently reported from micropillar compression of a range of brittle materials, such as Si, [29][30][31] GaAs, [32] GaN, [15,33] MgO, [34] ZrB 2 , [35] AlN, [36] and perovskite oxides. [37] In those cases, plastic deformation generally proceeds through strain bursts indicative of prevalent crystallographic slip.…”