Mechanical behavior — material with highest malleability (from given set) Malleability is the ability of a material to be hammered or rolled into thin sheets. Which of the following exhibits the highest malleability among the listed options?

Introduction / Context:
Malleability (sheet-forming ability) and ductility (wire-drawing ability) are two different measures of plastic deformation. Recognizing which metals are most malleable guides forming processes such as rolling and hammering.

Given Data / Assumptions:

• Compare common engineering metals: lead, copper, aluminium, wrought iron.
• Room-temperature forming behavior is implied.

Concept / Approach:
Lead is very soft and exhibits excellent malleability at room temperature, allowing it to be readily hammered into thin sheets (historically used for roofing and shielding). Copper and aluminium are also malleable but generally not as readily deformable into sheet at the same low stresses and without significant work hardening. Wrought iron is tougher and less malleable at room temperature.

Step-by-Step Solution:
Assess each metal’s plastic deformation behavior at room temperature.Lead shows the greatest ease of compression plasticity (sheet forming) among the listed choices.Therefore select lead as the most malleable among the given options.

Verification / Alternative check:
Standard material property tables and forming practice confirm lead’s high malleability; gold and silver surpass lead in absolute malleability but are not options here.

Why Other Options Are Wrong:

• Copper: very malleable, but typically not as easy to sheet as lead at room temperature without higher loads.
• Aluminium: malleable, but again usually below lead in malleability at ambient conditions.
• Wrought iron: stronger, less malleable in thin-sheet forming compared to soft lead.

Common Pitfalls:

• Confusing malleability with ductility; copper and aluminium are highly ductile but the question is about sheet forming.

Final Answer:
Lead