What are the two modes of fracture described?

• A. Brittle and transgranular
• B. Brittle and Ductile
• C. Creep and fatigue
• D. Elastic and plastic

Answer: (B)

In fracture behavior, materials fail in two broad ways: brittle fracture and ductile fracture. Brittle fracture happens with little or no plastic deformation—the material breaks suddenly, often at low temperatures or high strain rates, and fracture surfaces look flat and faceted. Ductile fracture, on the other hand, involves significant plastic deformation before final break. The material necks, elongates, and the fracture surface develops features like dimples from microvoid coalescence, indicating substantial energy absorption before failure. The other terms describe different ideas (creep and fatigue are time- or cycle-dependent damage; elastic vs plastic describes deformation before fracture; transgranular is a path of crack propagation within a brittle fracture) but do not represent the two main modes of fracture themselves. Therefore, the best answer is brittle and ductile.