Editing Scandium (section)

===Aluminium alloys===
{{Main|Aluminium–scandium alloys}}
[[File:Mig-29 on landing.jpg|thumb|right |Parts of the [[Mikoyan-Gurevich MiG-29|MiG-29]] are made from Al-Sc alloy.<ref name="Ahmad2003">{{cite journal|doi=10.1007/s11837-003-0224-6|title=The properties and application of scandium-reinforced aluminum|date=2003|first= Zaki|last= Ahmad|journal=JOM|volume=55|page=35|issue=2|bibcode= 2003JOM....55b..35A|s2cid=8956425}}</ref>]]
The main application of scandium by weight is in aluminium-scandium alloys for minor aerospace industry components. These alloys contain between 0.1% and 0.5% of scandium. They were used in Russian military aircraft, specifically the [[Mikoyan-Gurevich MiG-21]] and [[Mikoyan MiG-29|MiG-29]].<ref name="Ahmad2003" />

The addition of scandium to aluminium limits the grain growth in the heat zone of welded aluminium components. This has two beneficial effects: the precipitated {{chem2|Al3Sc}} forms smaller crystals than in other [[aluminium alloy]]s,<ref name="Ahmad2003" /> and the volume of precipitate-free zones at the grain boundaries of age-hardening aluminium alloys is reduced.<ref name="Ahmad2003" /> The {{chem2|Al3Sc}} precipitate is a coherent precipitate that strengthens the aluminum matrix by applying elastic strain fields that inhibit dislocation movement (i.e., plastic deformation). {{chem2|Al3Sc}} has an equilibrium L1<sub>2</sub> superlattice structure exclusive to this system.<ref>{{Cite journal|last1=Knipling|first1=Keith E.|last2=Dunand|first2=David C.|last3=Seidman|first3=David N.|date=2006-03-01|title=Criteria for developing castable, creep-resistant aluminum-based alloys – A review|url=https://www.hanser-elibrary.com/doi/abs/10.3139/146.101249|journal=Zeitschrift für Metallkunde|volume=97|issue=3|pages=246–265|doi=10.3139/146.101249|s2cid=4681149|issn=0044-3093}}</ref> 

A fine dispersion of nano scale precipitate can be achieved via heat treatment that can also strengthen the alloys through order hardening.<ref>{{Cite journal|last1=Knipling|first1=Keith E.|last2=Karnesky|first2=Richard A.|last3=Lee|first3=Constance P.|last4=Dunand|first4=David C.|last5=Seidman|first5=David N.|date=2010-09-01|title=Precipitation evolution in Al–0.1Sc, Al–0.1Zr and Al–0.1Sc–0.1Zr (at.%) alloys during isochronal aging|url=http://www.sciencedirect.com/science/article/pii/S1359645410003393|journal=Acta Materialia|language=en|volume=58|issue=15|pages=5184–5195|doi=10.1016/j.actamat.2010.05.054|bibcode=2010AcMat..58.5184K|issn=1359-6454}}</ref> Recent developments include the additions of transition metals such as [[zirconium]] (Zr) and rare earth metals like [[erbium]] (Er) produce shells surrounding the spherical {{chem2|Al3Sc}} precipitate that reduce coarsening.<ref>{{Cite journal|last1=Booth-Morrison|first1=Christopher|last2=Dunand|first2=David C.|last3=Seidman|first3=David N.|date=2011-10-01|title=Coarsening resistance at 400°C of precipitation-strengthened Al–Zr–Sc–Er alloys|url=http://www.sciencedirect.com/science/article/pii/S135964541100543X|journal=Acta Materialia|language=en|volume=59|issue=18|pages=7029–7042|doi=10.1016/j.actamat.2011.07.057|bibcode=2011AcMat..59.7029B|issn=1359-6454}}</ref> 

These shells are dictated by the diffusivity of the alloying element and lower the cost of the alloy due to less Sc being substituted in part by Zr while maintaining stability and less Sc being needed to form the precipitate.<ref>{{Cite journal|last1=De Luca|first1=Anthony|last2=Dunand|first2=David C.|last3=Seidman|first3=David N.|date=2016-10-15|title=Mechanical properties and optimization of the aging of a dilute Al-Sc-Er-Zr-Si alloy with a high Zr/Sc ratio|journal=Acta Materialia|language=en|volume=119|pages=35–42|doi=10.1016/j.actamat.2016.08.018|bibcode=2016AcMat.119...35D|issn=1359-6454|doi-access=free}}</ref> These have made {{chem2|Al3Sc}} somewhat competitive with titanium alloys along with a wide array of applications. However, [[titanium alloy]]s, which are similar in lightness and strength, are cheaper and much more widely used.<ref name="Schwarz2004">{{cite book|url=https://books.google.com/books?id=aveTxwZm40UC&pg=PA2274|page=2274|author=Schwarz, James A.|author2=Contescu, Cristian I.|author3=Putyera, Karol |publisher=CRC Press|date= 2004|isbn=978-0-8247-5049-7|title=Dekker encyclopédia of nanoscience and nanotechnology|volume=3}}</ref>

The alloy {{chem2|Al20Li20Mg10Sc20Ti30}} is as strong as titanium, light as aluminium, and hard as some ceramics.<ref>{{Cite journal |doi = 10.1080/21663831.2014.985855|title = A Novel Low-Density, High-Hardness, High-entropy Alloy with Close-packed Single-phase Nanocrystalline Structures|journal = Materials Research Letters|volume = 3|issue = 2|pages = 95–99|year = 2015|last1 = Youssef|first1 = Khaled M.|last2 = Zaddach|first2 = Alexander J.|last3 = Niu|first3 = Changning|last4 = Irving|first4 = Douglas L.|last5 = Koch|first5 = Carl C.|doi-access = free}}</ref>

Some items of sports equipment, which rely on lightweight high-performance materials, have been made with scandium-aluminium alloys, including [[baseball bat]]s,<ref name="bat">{{cite journal|title= A batty business: Anodized metal bats have revolutionized baseball. But are finishers losing the sweet spot?|journal= Metal Finishing|volume= 104 |page= 61|doi= 10.1016/S0026-0576(06)80099-1|date= 2006|first= Steve|last= Bjerklie|issue= 4}}</ref> tent poles and [[bicycle frame]]s and [[list of bicycle parts|components]].<ref>{{cite web|url= http://www.eastonbike.com/downloadable_files_unprotected/r&d_files/R&D-03%20Scandium.pdf|title= Easton Technology Report: Materials / Scandium|publisher= EastonBike.com|access-date= 2009-04-03}}</ref> [[Lacrosse sticks]] are also made with scandium. The American firearm manufacturing company [[Smith & Wesson]] produces semi-automatic pistols and revolvers with frames of scandium alloy and cylinders of titanium or carbon steel.<ref name="James2004">{{cite book|author=James, Frank|title=Effective handgun defense|url=https://books.google.com/books?id=XT5TRli0OdcC&pg=PA207|access-date=2011-06-08|date=15 December 2004|publisher=Krause Publications|isbn=978-0-87349-899-9|pages=207–}}{{Dead link|date=August 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref name="Sweeney2004">{{cite book|author=Sweeney, Patrick|title=The Gun Digest Book of Smith & Wesson|url=https://books.google.com/books?id=eBxEBgJBG0MC&pg=PA34|access-date=2011-06-08|date=13 December 2004|publisher=Gun Digest Books|isbn=978-0-87349-792-3|pages=34–}}{{Dead link|date=August 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

Since 2013, Apworks GmbH, a spin-off of Airbus, have marketed a high strength Scandium containing aluminium alloy processed using metal 3D-Printing (Laser Powder Bed Fusion) under the trademark [[Scalmalloy]] which claims very high strength & ductility.<ref>{{cite web|url = https://www.tctmagazine.com/additive-manufacturing-3d-printing-news/apworks-metal-additive-manufacturing-material-formula-1/ |title = APWORKS' Scalmalloy metal additive manufacturing material approved for use in Formula 1 |date = 2 July 2020 |publisher = TCT |access-date=2023-10-11}}</ref>