Which statement describes brittle fracture?

• A. Slow crack propagation with warnings
• B. Rapid crack propagation with little warning
• C. Cup-cone fracture surface
• D. Necking before fracture

Answer: (B)

Brittle fracture happens when a crack grows very quickly with almost no plastic deformation and little warning before it fails. That rapid, unheralded propagation is the hallmark, so the statement describing rapid crack propagation with little warning is the best fit.

In contrast, slow crack growth with warnings is more typical of fatigue or environmentally assisted cracking, and a cup-cone fracture surface or necking before fracture signals ductile behavior where the material deforms plastically and white necks out before breaking.