Dendrite (metal)

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For other uses of "dendrite", see dendrite (disambiguation).

A dendrite in metallurgy is a characteristic tree-like structure of crystals growing as molten metal freezes, the shape produced by faster growth along energetically favourable crystallographic directions. This dendritic growth has large consequences in regards to material properties. If the metal is cooled slowly, dendritic growth will occur for longer periods of time, and therefore the resulting dendrites will grow to a larger size. This lowers the metal's elastic modulus, due to large grain size. Conversely, a short, rapid cooling cycle will increase the elastic modulus of a metal, as the resulting dendrites will be small (therefore small grains). One application where dendritic growth and resulting material properties can be seen is the process of welding (where this growth appears in the Heat-affected zone, or HAZ).

Dendrites also form during the freezing of many nonmetallic substances such as ice.

Dendrites usually form in rapid cooling, or non-equilibrium conditions.

Common dendritic metal material is nickel carbonyl, where the particles have a classical "spiky" morphology.