Ductility

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The Main Idea

Ductility is a solids ability to deform under tensile stress. It is similar to malleability, which characterizes a materials ability to deform under an applied stress. Both of these are plastic properties of materials. While they are often similar, sometimes a materials ductility is independent from its malleability. Materials with metallic bond have much higher ductility's du to the mobile electrons that tend to deform, rather than fracture. Therefore the most common ductile materials are steel, copper, gold and aluminum. Ductility is an important property in material science and metal-working industries, where solids are deformed nd molded with outside forces.

Fig 1. Highly brittle fracture
Fig 2. Semi-ductile fracture

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A Mathematical Model

Mathematically, ductility can be defined as the fracture strain, or the tensile strain along one axis that causes a fracture to occur. Fractures range from brittle fractures (Fig 1) to fully ductile fractures (Fig 2), resulting in very different physical appearances associated with the different types. This can be modeled on a stress/strain curve (https://www.nde-ed.org/EducationResources/CommunityCollege/Materials/Graphics/Mechanical/Brittle-Ductile.gif) showing where fracture occurs along the graph.

Connectedness

As an Aerospace major, determining the correct material for components can be high risk. Knowing different materials ranges of ductility, can be integral in choosing he best option. This is especially important in materials that have a high applied tensile strength.

History

Percy Williams Bridgman's findings on tensile strength and material properties led to much of what is known about ductility, including that it is highly influenced by temperature and pressure. these findings led him to win the 1946 Nobel Prize in physics.

See also

Further reading

Books, Articles or other print media on this topic

External links

[1]


References

https://en.wikipedia.org/wiki/Ductility https://en.wikibooks.org/wiki/Advanced_Structural_Analysis/Part_I_-_Theory/Materials/Properties/Ductility https://en.wikipedia.org/wiki/Ductility#/media/File:Ductility.svg https://en.wikipedia.org/wiki/Percy_Williams_Bridgman