What does the term 'ductile fracture' describe?

Ductile fracture is characterized by significant plastic deformation that occurs prior to the material's failure. This type of fracture typically involves the material stretching and deforming under stress, allowing for energy absorption as the fracture progresses. When a material is subjected to a load that exceeds its yield strength, it will undergo plastic deformation, which means it will change shape without breaking immediately.

During a ductile fracture, the material shows signs of necking, or localized deformation, leading to a more gradual failure rather than a brittle, instantaneous break. This deformation is crucial because it provides visual warnings of potential failure, allowing time for preventive measures. The presence of significant plastic deformation also indicates that the material has a certain toughness, which is an important property in many engineering applications.

Fractures that do not involve any plastic deformation, such as those described in the other options, do not fit the definition of ductile fractures. Instead, those fractures are typically classified as brittle fractures, where the material breaks suddenly with little or no deformation observed prior to failure.