Editing Ductility (section)

==Materials science==
[[File:Au atomic wire.jpg|thumb|Gold is extremely ductile. It can be drawn into a monatomic wire, and then stretched more before it breaks.<ref>{{cite book |doi=10.5772/62288 |isbn=978-953-51-2252-4 |chapter=Combined Transmission Electron Microscopy – In situ Observation of the Formation Process and Measurement of Physical Properties for Single Atomic-Sized Metallic Wires |author=Masuda, Hideki |title=Modern Electron Microscopy in Physical and Life Sciences |editor=Janecek, Milos |editor2=Kral, Robert |publisher=InTech |year=2016|s2cid=58893669 }}</ref><!-- This is content from a predatory publisher (intechopen.com); recommend finding an alternative source for a comparable image, but I hesitate to remove the image at this time. -->]]

Ductility is especially important in [[metalworking]], as materials that crack, break or shatter under stress cannot be manipulated using [[Forming (metalworking)|metal-forming]] processes such as [[hammer]]ing, [[rolling (metalworking)|rolling]], [[drawing (metalworking)|drawing]] or [[Extrusion|extruding]]. Malleable materials can be formed cold using [[Stamping (metalworking)|stamping]] or [[Machine press|press]]ing, whereas brittle materials may be [[Casting|cast]] or [[Thermoforming|thermoformed]].

High degrees of ductility occur due to [[metallic bond]]s, which are found predominantly in metals; this leads to the common perception that metals are ductile in general.  In metallic bonds [[valence shell]] [[electron]]s are delocalized and shared between many atoms.  The [[delocalized electron]]s allow metal atoms to slide past one another without being subjected to strong repulsive forces that would cause other materials to shatter.

The ductility of [[steel]] varies depending on the alloying constituents. Increasing the levels of [[carbon]] decreases ductility. Many plastics and [[amorphous solid]]s, such as [[Play-Doh]], are also malleable. The most ductile metal is [[platinum]] and the most malleable metal is [[gold]].<ref>Vaccaro, John (2002) ''Materials handbook'', Mc Graw-Hill handbooks, 15th ed.</ref><ref>Schwartz, M. (2002) ''CRC encyclopedia of materials parts and finishes'', 2nd ed.</ref> When highly stretched, such metals distort via formation, reorientation and migration of [[dislocation]]s and [[Crystal twinning|crystal twins]] without noticeable hardening.<ref>{{cite journal|doi=10.1080/14686996.2019.1585145|pmid=30956731|pmc=6442207|title=Synthesis and modelling of the mechanical properties of Ag, Au and Cu nanowires|journal=Sci. Technol. Adv. Mater.|year=2019|volume=20|issue=1|pages=225–261|first1=Che|last1=Lah|first2=Nurul|last2=Akmal|first3=Sonia|last3=Trigueros |bibcode=2019STAdM..20..225L}}</ref>