Ductility Definition — MFDS Part 1 MCQ

Correct answer: D — Ductility

The correct answer is **A. Ductility**. Ductility is the ability of a material to undergo substantial permanent deformation under tensile loading before fracture; it is classically illustrated by the ability to be drawn into a wire. Malleability instead describes permanent deformation under compression, commonly expressed as the ability to be hammered or rolled into a thin sheet. Brittleness is fracture with little preceding plastic deformation. Toughness is the energy a material can absorb before fracturing, whereas elasticity is the ability to return to the original dimensions after removal of a load. Therefore, the reference to drawing the material into wire uniquely identifies ductility.

Reference: Xu Z-K et al. Iterative sublattice amorphization facilitates exceptional processability in inorganic semiconductors. Nature Materials. 2025. https://www.rcseng.ac.uk/-/media/files/rcs/education-and-exams/exams/lds-docs/lds-2022-docs-and-regs/lds-suggested-reading.pdf