ESS

Ductility

Malleability

Ductility is the ability of a solid material to undergo tensile stress. This property of a solid material can be measured and describes the extent to which the solid material can be plastically deformed without fracture. It is often depicted by the ability of the solid to stretch into a wire when pulled at the ends.

 The mechanical property of ductility is quantified by the fracture strain, which is the strain at which the material fractures when increasing tensile stresses are applied along a single axis. The reduction of the area from the initial point to the fracture during the test can also be considered as a measure.

Ductility is a property specially looked for in metals. Metals have a very high ductility. Therefore, metals can be easily manipulated compared to other solid materials.

Malleability is the ability of solid materials to undergo compressive stress.  Metals are highly malleable compared to non-metal materials. Therefore, metals can be shaped using forming methods such as forging, rolling, extrusion and indenting.

Since gold is highly malleable they can be forged into very thin foils, sometimes only few atoms thick.

Brittleness

Hardness

A material is brittle if, when subjected to stress, it breaks without significant deformation (strain). Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a snapping sound. Brittle materials include most ceramics and glasses (which do not deform plastically) and some polymers, such as PMMA and polystyrene.

Many steels become brittle at low temperatures (see ductile-brittle transition temperature), depending on their composition and processing.

Hardness is a measure of how resistant solid matter is to various kinds of permanent shape change when a compressive force is applied. Some materials (e.g. metals) are harder than others (e.g. plastics). Macroscopic hardness is generally characterize by strong intermolecular bonds, but the behaviour of solid materials under force is complex; therefore, there are different measurements of hardness: scratch hardness, indentation hardness, and rebound hardness.

Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity.

Common examples of hard matter are ceramics, concrete, certain metals, and super hard materials, which can be contrasted