Which materials are known for having little or no yielding and can fracture suddenly?

Brittle materials are characterized by their tendency to fracture suddenly under stress, often without any significant prior deformation. This behavior contrasts sharply with ductile materials, which can undergo considerable plastic deformation before failure. Brittle materials, such as ceramics, glass, and certain metals under specific conditions, exhibit little to no yielding, meaning they do not deform appreciably when stressed within their elastic limits. Instead, they reach their ultimate strength and break almost instantaneously, which can be quite hazardous in structural applications where unexpected failures occur.

Elastic materials, while capable of returning to their original shape after deformation, still do not fracture abruptly; they behave predictably until the yield point is reached, at which they show significant deformation. Plastic materials, on the other hand, are defined by their ability to undergo permanent deformation without fracture when stressed, which is a clear distinction from brittle behavior. Thus, the defining quality of brittle materials being their sudden fracture under stress aligns them as the correct choice for this question.