Malleability

Malleability is a substance's ability to deform under pressure (compressive stress). If malleable, a material may be flattened into thin sheets by hammering or rolling. Malleable materials can be flattened into metal leaf. One well-known type of metal leaf is gold leaf. Many metals with high malleability also have high ductility. Some do not; for example lead has low ductility but high malleability.

Malleability is a physical property of matter, usually metals. The property usually applies to the family groups 1 to 12 on the modern periodic table of elements. It is the ability of a solid to bend or be hammered into other shapes without breaking. Examples of malleable metals are gold, iron, aluminum, copper, silver, and lead.

Gold and silver are highly malleable. When a piece of hot iron is hammered it takes the shape of a sheet. The property is not seen in non-metals. Non-malleable metals may break apart when struck by a hammer. Malleable metals usually bend and twist in various shapes.

Zinc is malleable at temperatures between 100 and 200 °C but is brittle at other temperatures.

How is malleability measured?

There are two ways to measure it. The first is to measure the pressure or compressive stress that a material withstands before it breaks. The other test involves measuring the thickness of a metal sheet before it breaks.

Malleability Media

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  Tensile test of an Al-Mg-Si alloy. The local necking and the cup and cone fracture surfaces are typical for ductile metals.

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  This tensile test of a nodular cast iron demonstrates low ductility.

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  Gold is extremely ductile. It can be drawn into a monatomic wire, and then stretched more before it breaks.

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  Schematic appearance of round metal bars after tensile testing.*(a) Brittle fracture*(b) Ductile fracture*(c) Completely ductile fracture

Related pages

• Ductility