In materials science, what is a brittle material?

A brittle material is characterized by its tendency to fracture without undergoing substantial plastic deformation. This means that when a brittle material is subjected to stress, it will reach a point where it fails suddenly and catastrophically, often without any prior indication of strain or deformation. The fracture occurs in a very short time frame, typically accompanied by a clean break rather than a gradual yielding.

This behavior is in contrast to ductile materials, which can absorb energy and deform significantly before failing. Brittle materials are important in various engineering applications because they can be very strong and rigid but may also pose risks if their failure occurs unexpectedly.

In the context of the other options, the other descriptions do not accurately capture the essential nature of brittleness. The first option relates to ductility, emphasizing deformation before failure, while the last two options reference properties related to moldability and thermal conductivity, which do not pertain to the concept of brittleness at all.