Brittle engineering ceramics usually fail due to flaws that are distributed in the material. Their strength depends on the length of the major flaw, which may be different from specimen to specimen, being described by a probability function. If the material exibits a statistical distribution of independent flaws and the weak link hypothesis is fulfilled, i.e., the specimen fails if its weakest ...

Aerogels refer to a new class of materials holding air in their structure. They are highly porous solids having a large inner surface area. They are extremely light, low heat conductive, and high sound absorbent materials. Therefore, aerogels have excellent performance in applications such as heat insulators, particle filters, particle trappers, and catalyst carriers 1 . Aerogels are prepared s...

Mineralized biological materials such as bone, sea sponges or diatoms provide load-bearing and armor functions and universally feature structural hierarchies from nano to macro. Here we report a systematic investigation of the effect of hierarchical structures on toughness and defect-tolerance based on a single and mechanically inferior brittle base material, silica, using a bottom-up approach ...

We have demonstrated the ability to perform a ductile material removal operation, via single-point diamond turning, on single-crystal silicon carbide (6H). To our knowledge, this is the first reported work on the ductile machining of single-crystal silicon carbide (SiC). SiC experiences a ductile-to-brittle transition similar to other nominally brittle materials such as silicon, germanium, and ...

Tearing a thin sheet by forcing a rigid object through it leads to complex crack morphologies; a single oscillatory crack arises when a tool is driven laterally through a brittle sheet, while two diverging cracks and a series of concertinalike folds forms when a tool is forced laterally through a ductile sheet. On the other hand, forcing an object perpendicularly through the sheet leads to radi...