Materials science — definition check In mechanical metallurgy, the ability of a material to undergo large permanent (plastic) deformation under the application of a tensile force without fracturing is called ductility. State whether this statement is correct.

Introduction / Context:
Ductility is a core mechanical property used to characterize metals and engineering materials. It indicates how much plastic deformation a material can sustain in tension before fracture. This property is critical for processes such as wire drawing, sheet metal forming, and for assessing failure modes in design and fracture prevention.

Given Data / Assumptions:

• Tensile loading is the primary mode considered when defining ductility.
• Permanent deformation means plastic deformation, not elastic.
• Standard measures include percentage elongation and percentage reduction in area on a tensile specimen.

Concept / Approach:
Ductility relates to the ability to accommodate plastic strain under tensile stress. In a stress–strain test, a ductile material shows a long plastic region after yield, with significant elongation and necking prior to fracture. High ductility often correlates with good formability and the ability to redistribute stresses around flaws, delaying catastrophic fracture.

Step-by-Step Solution:
Recognize the definition: “large permanent deformation under tensile force” matches the standard meaning of ductility.Differentiate from toughness: toughness concerns energy absorption to fracture (area under the stress–strain curve), not simply large plastic strain in tension.Differentiate from malleability: malleability is the ability to undergo plastic deformation under compressive loading (e.g., rolling into sheet), while ductility emphasizes tensile loading.Therefore the statement provided is correct.

Verification / Alternative check:
Handbook definitions express ductility through % elongation and % reduction in area after a standardized tensile test (e.g., gauge length elongation and necked diameter). These quantify the “large permanent deformation” described.

Why Other Options Are Wrong:
“Incorrect; that is toughness” confuses two different properties. “Incorrect; that is malleability only” ignores the compression versus tension distinction. “Correct only for non-ferrous metals” is false; steels can be highly ductile depending on composition and heat treatment.

Common Pitfalls:
Equating high strength with low ductility automatically—some alloys achieve useful combinations. Also, using elastic elongation as evidence of ductility is incorrect; ductility is about plastic strain.

Final Answer:
Correct