Malleability

Malleability is a property of solids, most commonly metals, that permits substantial plastic deformation under shaping forces without fracturing. It is a form of plasticity closely related to ductility, which describes the ability to be drawn into wires under tensile stress. In industrial practice, malleability enables processes such as rolling, hammering, and pressing to form thin sheets or complex shapes.

The microscopic basis lies in the movement of dislocations and the interaction of crystal grains. When a metal is deformed, dislocations glide and multiply; grain boundaries and crystal orientation influence how easily slip occurs. Higher temperatures generally increase malleability by facilitating dislocation motion, while work hardening or alloying can reduce it unless annealed. Microstructure, including grain size and phase composition, strongly affects malleability.

Gold, platinum, and silver are noted for high malleability; aluminum and copper are also readily formed into sheets. Ceramics and many polymers exhibit different deformation behaviors; among metals, those with simple crystal structures and relatively pure compositions tend to be more malleable, whereas brittle materials display low malleability. Malleability is exploited in sheet metal fabrication, coinage, jewelry, packaging, and various architectural and automotive applications.

Unlike a single numeric property, malleability is typically described qualitatively or through processing performance. It correlates with ductility but is not identical. In testing, malleability is inferred from a material’s ability to form sheets or resist cracking under shaping operations; related measures come from hardness, toughness, and elongation tests in tensile specimens.