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Intermetallic
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<h2 id="definitions">Definitions</h2> <h3>Research definition</h3> <p>In 1967 Gustav Ernst Robert Schulze [de] defined intermetallic compounds as <i>solid phases containing two or more metallic elements, with optionally one or more non-metallic elements, whose crystal structure differs from that of the other constituents</i>.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> This definition includes: </p> <ul><li>Electron (or <a href="/facts/Hume-Rothery_rules/hhXcQ9oC">Hume-Rothery</a>) compounds</li> <li>Size packing phases. e.g. <a href="/facts/Laves_phase/usmGNgRl">Laves phases</a>, <a href="/facts/Frank%25E2%2580%2593Kasper_phases/WuEkYTva">Frank–Kasper phases</a> and <a href="/facts/Nowotny_phase/uz4e0KkB">Nowotny phases</a></li> <li><a href="/facts/Zintl_phase/RdV0yDXf">Zintl phases</a></li></ul> <p>The definition of metal includes: </p> <ul><li><a href="/facts/Post-transition_metal/wjp3aeGn">Post-transition metals</a>, i.e. <a href="/facts/Aluminium/7wmR8jYE">aluminium</a>, <a href="/facts/Gallium/EucevDs9">gallium</a>, <a href="/facts/Indium/zRq3stVb">indium</a>, <a href="/facts/Thallium/v35pGMJB">thallium</a>, <a href="/facts/Tin/obW9mqc3">tin</a>, <a href="/facts/Lead/EYljasJN">lead</a>, and <a href="/facts/Bismuth/75FLjkoX">bismuth</a>.</li> <li><a href="/facts/Metalloid/uMFVXuTq">Metalloids</a>, e.g. <a href="/facts/Silicon/cgWx0hdr">silicon</a>, <a href="/facts/Germanium/wtoALHGs">germanium</a>, <a href="/facts/Arsenic/k1c4f44D">arsenic</a>, <a href="/facts/Antimony/YsA7lVgT">antimony</a> and <a href="/facts/Tellurium/v7QvfIvS">tellurium</a>.</li></ul> <p>Homogeneous and heterogeneous <a href="/facts/Solid_solution/Mla7z8dc">solid solutions</a> of metals, and <a href="/facts/Interstitial_compound/2JH71t2U">interstitial compounds</a> such as <a href="/facts/Carbide/xfCMTjYJ">carbides</a> and <a href="/facts/Nitride/9vkrCbJ4">nitrides</a> are excluded under this definition. However, interstitial intermetallic compounds are included, as are alloys of intermetallic compounds with a metal. </p> <h3>Common use</h3> <p>In common use, the research definition, including <a href="/facts/Post-transition_metal/wjp3aeGn">post-transition metals</a> and <a href="/facts/Metalloid/uMFVXuTq">metalloids</a>, is extended to include compounds such as <a href="/facts/Cementite/BvMdo027">cementite</a>, Fe3C. These compounds, sometimes termed <a href="/facts/Interstitial_compound/2JH71t2U">interstitial compounds</a>, can be <a href="/facts/Stoichiometric/I5p9cJzV">stoichiometric</a>, and share properties with the above intermetallic compounds. </p> <h3>Complexes</h3> <p>The term intermetallic is used<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> to describe compounds involving two or more metals such as the <a href="/facts/Cyclopentadienyl_complex/rezSmzLI">cyclopentadienyl complex</a> Cp6Ni2Zn4. </p> <h3>B2</h3> <p>A <a href="/facts/Strukturbericht_designation/9uLQ8Ijs">B2</a> intermetallic compound has equal numbers of atoms of two metals such as aluminum and iron, arranged as two interpenetrating simple cubic lattices of the component metals.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> </p> <h2 id="properties">Properties</h2> <p>Intermetallic compounds are generally brittle at room temperature and have high melting points. Cleavage or intergranular fracture modes are typical of intermetallics due to limited independent <a href="/facts/Slip_(materials_science)/P29xbKBu">slip</a> systems required for plastic deformation. However, some intermetallics have ductile fracture modes such as Nb–15Al–40Ti. Others can exhibit improved <a href="/facts/Ductility/SBJsahEk">ductility</a> by alloying with other elements to increase grain boundary cohesion. Alloying of other materials such as <a href="/facts/Boron/Pmwgd7Mf">boron</a> to improve grain boundary cohesion can improve ductility.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> They may offer a compromise between <a href="/facts/Ceramic/9JKudpqX">ceramic</a> and metallic properties when hardness and/or resistance to high temperatures is important enough to sacrifice some <a href="/facts/Toughness/1gEIUdBu">toughness</a> and ease of processing. They can display desirable <a href="/facts/Magnetism/eo75vApl">magnetic</a> and chemical properties, due to their strong internal order and mixed (<a href="/facts/Metallic_bond/Ht958du4">metallic</a> and <a href="/facts/Covalent_bond/EzMLf3Pz">covalent</a>/<a href="/facts/Ionic_bond/R6nUJI5u">ionic</a>) bonding, respectively. Intermetallics have given rise to various novel materials developments. </p> Physical properties of intermetallics<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a><table><tbody><tr><th>Intermetallic Compound</th><th>Melting Temperature<p>(°C)</p></th><th>Density<p>(kg/m3)</p></th><th>Young's Modulus (GPa)</th></tr><tr><td>FeAl</td><td>1250–1400</td><td>5600</td><td>263</td></tr><tr><td>Ti3Al</td><td>1600</td><td>4200</td><td>210</td></tr><tr><td>MoSi2</td><td>2020</td><td>6310</td><td>430</td></tr></tbody></table> <h2 id="applications">Applications</h2> <p>Examples include <a href="/facts/Alnico/gEW0Itz3">alnico</a> and the <a href="/facts/Hydrogen_storage/KPqx6qNG">hydrogen storage</a> materials in <a href="/facts/Nickel_metal_hydride/EvCG8loy">nickel metal hydride</a> batteries. <a href="/facts/Nickel_aluminide/QbL8b64y">Ni3Al</a>, which is the hardening phase in the familiar nickel-base <a href="/facts/Superalloy/UwshApNV">super alloys</a>, and the various <a href="/facts/Titanium/53ArnDoy">titanium</a> aluminides have attracted interest for <a href="/facts/Turbine_blade/yY8jFPgl">turbine blade</a> applications, while the latter is also used in small quantities for <a href="/facts/Grain_refinement/Dao0UIh5">grain refinement</a> of <a href="/facts/Titanium_alloy/cMFhSKSL">titanium alloys</a>. <a href="/facts/Silicide/NyxslNNN">Silicides</a>, intermetallics involving silicon, serve as barrier and contact layers in <a href="/facts/Microelectronics/HzCusb86">microelectronics</a>.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> Others include: </p> <ul><li><a href="/facts/Magnetic_material/vvrg6VSk">Magnetic materials</a> e.g. <a href="/facts/Alnico/gEW0Itz3">alnico</a>, <a href="/facts/Sendust/tPg6XJXp">sendust</a>, Permendur, FeCo, <a href="/facts/Terfenol-D/V8IEwr4L">Terfenol-D</a></li> <li><a href="/facts/Superconductors/pqQAlSzJ">Superconductors</a> e.g. <a href="/facts/A15_phases/I199cR4x">A15 phases</a>, <a href="/facts/Niobium-tin/QnRWPr70">niobium-tin</a></li> <li><a href="/facts/Hydrogen_storage/KPqx6qNG">Hydrogen storage</a> e.g. AB5 compounds (<a href="/facts/Nickel_metal_hydride_batteries/EvCG8loy">nickel metal hydride batteries</a>)</li> <li><a href="/facts/Shape_memory_alloy/dWInaJpt">Shape memory alloys</a> e.g. Cu-Al-Ni (alloys of Cu3Al and nickel), <a href="/facts/Nitinol/0qoDhI0w">Nitinol</a> (NiTi)</li> <li>Coating materials e.g. NiAl</li> <li>High-temperature <a href="/facts/Structural_materials/okUKPFUQ">structural materials</a> e.g. <a href="/facts/Nickel_aluminide/QbL8b64y">nickel aluminide</a>, Ni3Al</li> <li><a href="/facts/Dental_amalgam/1tJBCfwR">Dental amalgams</a>, which are alloys of intermetallics Ag3Sn and Cu3Sn</li> <li><a href="/facts/Semiconductor_device/6W3ryr50">Gate contact</a>/ <a href="/facts/Barrier_layer/fqlG74DA">barrier layer</a> for <a href="/facts/Microelectronics/HzCusb86">microelectronics</a> e.g. <a href="/facts/Titanium_disilicide/gBWH22fQ">TiSi2</a><a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a>: 692 </li> <li><a href="/facts/Laves_phase/usmGNgRl">Laves phases</a> (AB2), e.g., MgCu2, MgZn2 and MgNi2.</li></ul> <p>The unintended formation of intermetallics can cause problems. For example, <a href="/facts/Gold-aluminium_intermetallic/I3DKU2qB">intermetallics of gold and aluminium</a> can be a significant cause of <a href="/facts/Wire_bonding/e0qvKlGv">wire bond</a> failures in <a href="/facts/Semiconductor_device/6W3ryr50">semiconductor devices</a> and other <a href="/facts/Microelectronics/HzCusb86">microelectronics</a> devices. The management of intermetallics is a major issue in the reliability of <a href="/facts/Solder/GBvJH75t">solder</a> joints between electronic components. </p> <h2 id="intermetallic-particles">Intermetallic particles</h2> <p class="note">Main article: <a href="/facts/Intermetallic_particle/3Fk92kGs">Intermetallic particle</a></p> <p><a href="/facts/Intermetallic_particle/3Fk92kGs">Intermetallic particles</a> often form during solidification of metallic alloys, and can be used as a <a href="/facts/Strengthening_mechanisms_of_materials/yyffj3m3">dispersion strengthening</a> mechanism.<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a> </p> <h2 id="history">History</h2> <p>Examples of intermetallics through history include: </p> <ul><li>Roman yellow <a href="/facts/Brass/pe8EHk6x">brass</a>, CuZn</li> <li>Chinese high tin <a href="/facts/Bronze/YCYCVIKt">bronze</a>, Cu31Sn8</li> <li><a href="/facts/Type_metal/WpE7fW72">Type metal</a>, SbSn</li> <li>Chinese <a href="/facts/Cupronickel/KE4WSdu3">white copper</a>, CuNi <a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a></li></ul> <p>German type metal is described as breaking like glass, without bending, softer than copper, but more fusible than lead.<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a>: 454 The chemical formula does not agree with the one above; however, the properties match with an intermetallic compound or an alloy of one. </p> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Complex_metallic_alloys/5MbDnCbF">Complex metallic alloys</a></li> <li><a href="/facts/Kirkendall_effect/WzIuqqzC">Kirkendall effect</a></li> <li><a href="/facts/Maraging_steel/rwc0qRpQ">Maraging steel</a></li> <li><a href="/facts/Metallurgy/1SANyxX4">Metallurgy</a></li> <li><a href="/facts/Solid_solution/Mla7z8dc">Solid solution</a></li></ul> <h2 id="sources">Sources</h2> <ul><li>Sauthoff, Gerhard [in German] (1995). <a href="https://books.google.com/books?id=p75RAAAAMAAJ"><i>Intermetallics</i></a>. Wiley-VCH. pp. 1–165. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3527293209.</li> <li>Sauthoff, Gerhard [in German] (2006). "Intermetallics". <i>Ullmann's Encyclopedia of Industrial Chemistry</i>. Wiley Interscience. pp. 393–423. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1002%2F14356007.e14_e01.pub2">10.1002/14356007.e14_e01.pub2</a>. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-527-30385-4.</li></ul> <h2 id="external-links">External links</h2> <ul><li><a href="http://www.elsevier.com/wps/find/journaldescription.cws_home/423924/description#description"><i>Intermetallics</i></a>, scientific journal</li> <li><a href="https://web.archive.org/web/20051218202657/http://nepp.nasa.gov/wirebond/intermetallic_creation_and_growt.htm">"Intermetallic Creation and Growth"</a>. Archived from <a href="https://nepp.nasa.gov/wirebond/intermetallic_creation_and_growt.htm">the original</a> on December 18, 2005.</li> <li><a href="https://web.archive.org/web/20070329034903/http://www.spaceflight.esa.int/impress/#IMPRESS">"IMPRESS Intermetallics project"</a>. <i>www.spaceflight.esa.int</i>. Archived from <a href="http://www.spaceflight.esa.int/impress#IMPRESS">the original</a> on 2007-03-29. Retrieved 2024-12-22.</li> <li><a href="https://web.archive.org/web/20151210223620/https://www.ameslab.gov/mpc/video"><i>Video of an AB5 intermetallic compound solidifying/freezing</i></a>. Archived from <a href="https://www.ameslab.gov/mpc/video">the original</a> on December 10, 2015.</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Askeland, Donald R.; Wright, Wendelin J. (January 2015). "11-2 Intermetallic Compounds". The science and engineering of materials (Seventh ed.). Boston, MA. pp. 387–389. ISBN 978-1-305-07676-1. OCLC 903959750.{{cite book}}: CS1 maint: location missing publisher (link) <a href="978-1-305-07676-1" target="_blank">978-1-305-07676-1</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Panel On Intermetallic Alloy Development, Commission On Engineering And Technical Systems (1997). Intermetallic alloy development : a program evaluation. National Academies Press. p. 10. ISBN 0-309-52438-5. OCLC 906692179. <a href="0-309-52438-5" target="_blank">0-309-52438-5</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Soboyejo, W. O. (2003). "1.4.3 Intermetallics". Mechanical properties of engineered materials. Marcel Dekker. ISBN 0-8247-8900-8. OCLC 300921090. <a href="0-8247-8900-8" target="_blank">0-8247-8900-8</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Askeland, Donald R.; Wright, Wendelin J. (January 2015). "11-2 Intermetallic Compounds". The science and engineering of materials (Seventh ed.). Boston, MA. pp. 387–389. ISBN 978-1-305-07676-1. OCLC 903959750.{{cite book}}: CS1 maint: location missing publisher (link) <a href="978-1-305-07676-1" target="_blank">978-1-305-07676-1</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Hume-Rothery, W. (1955) [1948]. Electrons, atoms, metals and alloys (revised ed.). London: Louis Cassier Co., Ltd. pp. 316–317 – via the Internet Archive. <a href="https://archive.org/details/in.ernet.dli.2015.18295" target="_blank">https://archive.org/details/in.ernet.dli.2015.18295</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>G. E. R. Schulze: Metallphysik, Akademie-Verlag, Berlin 1967 <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999), Advanced Inorganic Chemistry (6th ed.), New York: Wiley-Interscience, ISBN 0-471-19957-5 <a href="0-471-19957-5" target="_blank">0-471-19957-5</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>"Wings of steel: An alloy of iron and aluminium is as good as titanium, at a tenth of the cost". The Economist. February 7, 2015. Retrieved February 5, 2015. E02715 <a href="https://www.economist.com/news/science-and-technology/21642107-alloy-iron-and-aluminium-good-titanium-tenth" target="_blank">https://www.economist.com/news/science-and-technology/21642107-alloy-iron-and-aluminium-good-titanium-tenth</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Soboyejo, W. O. (2003). "12.5 Fracture of Intermetallics". Mechanical properties of engineered materials. Marcel Dekker. ISBN 0-8247-8900-8. OCLC 300921090. <a href="0-8247-8900-8" target="_blank">0-8247-8900-8</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Askeland, Donald R.; Wright, Wendelin J. (January 2015). "11-2 Intermetallic Compounds". The science and engineering of materials (Seventh ed.). Boston, MA. pp. 387–389. ISBN 978-1-305-07676-1. OCLC 903959750.{{cite book}}: CS1 maint: location missing publisher (link) <a href="978-1-305-07676-1" target="_blank">978-1-305-07676-1</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Murarka, S.P. (June 1993). "Metallization: theory and practice for VLSI and ULSI". Choice Reviews Online. 30 (10): 30–5612-30-5612. doi:10.5860/choice.30-5612 (inactive 1 February 2025). ISSN 0009-4978.{{cite journal}}: CS1 maint: DOI inactive as of February 2025 (link) <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Ohring, Milton (2002). Materials Science of Thin Films. Academic Press. ISBN 9780125249751. <a href="9780125249751" target="_blank">9780125249751</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>Askeland, Donald R.; Wright, Wendelin J. (January 2015). "11-2 Intermetallic Compounds". The science and engineering of materials (Seventh ed.). Boston, MA. pp. 387–389. ISBN 978-1-305-07676-1. OCLC 903959750.{{cite book}}: CS1 maint: location missing publisher (link) <a href="978-1-305-07676-1" target="_blank">978-1-305-07676-1</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>"The Art of War by Sun Zi: A Book for All Times". China Today. Archived from the original on 2005-03-07. Retrieved 2022-11-25. <a href="https://web.archive.org/web/20050307083704/http://www.chinatoday.com.cn/English/e20026/sunzi1.htm" target="_blank">https://web.archive.org/web/20050307083704/http://www.chinatoday.com.cn/English/e20026/sunzi1.htm</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p>Long, George (1843). "Type-pounding". The Penny Cyclopædia of the Society for the Diffusion of Useful Knowledge. C. Knight. <a href="https://books.google.com/books?id=joN6G1T6ZHIC" target="_blank">https://books.google.com/books?id=joN6G1T6ZHIC</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> </ol>