sprød

Spröd is a German adjective meaning “brittle” or “fragile”, used to describe materials, substances, or structures that break or fracture easily under stress without appreciable deformation. In materials science, a spröde (brittle) material exhibits low ductility and toughness; it absorbs little energy before failure, often cracking along crystal planes or grain boundaries. Common examples include glass, ceramics, some high‑strength steels at low temperatures, and certain polymers when cooled. The opposite property is “zäh” (tough), referring to materials that can undergo significant plastic deformation before rupture.

The term appears in physics when discussing fracture mechanics, where the critical stress intensity factor (K_IC) determines a material’s resistance to crack propagation. Brittle fracture is typically rapid, trans‑granular or inter‑granular, and produces little macroscopic deformation. Temperature can influence brittleness; many metals become spröde below a ductile‑to‑brittle transition temperature, a phenomenon important for engineering design in cold environments.

In biology, spröd describes tissues or organs that are easily damaged, such as aged bone, cartilage, or certain plant stems that lack lignification. Medical literature may use “brittle” to characterize conditions like brittle‑bone disease (osteogenesis imperfecta) or brittle hair syndrome.

Etymologically, spröd derives from Middle High German “spröde”, related to Old High German “sprēd” and ultimately linked to the Proto‑Germanic root *sprēdaną, meaning “to break”. The word entered English in technical contexts as “brittle”, retaining the same connotations.

Understanding spröd behavior is essential for safety assessments, product design, and failure analysis across engineering, geology, and biomechanics, guiding the selection of appropriate materials and the implementation of design measures such as heat treatment, alloying, or composite reinforcement to mitigate brittleness.