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pressure allotropes subsection</span> </button> <ul id="toc-Standard_pressure_allotropes-sublist" class="vector-toc-list"> <li id="toc-Alpha_iron_(α-Fe)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Alpha_iron_(α-Fe)"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.1</span> <span>Alpha iron (α-Fe)</span> </div> </a> <ul id="toc-Alpha_iron_(α-Fe)-sublist" class="vector-toc-list"> <li id="toc-A2_critical_temperature_and_induction_heating" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#A2_critical_temperature_and_induction_heating"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.1.1</span> <span>A<sub>2</sub> critical temperature and induction heating</span> </div> </a> <ul id="toc-A2_critical_temperature_and_induction_heating-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Gamma_iron_(γ-Fe)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Gamma_iron_(γ-Fe)"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.2</span> <span>Gamma iron (γ-Fe)</span> </div> </a> <ul id="toc-Gamma_iron_(γ-Fe)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Delta_iron_(δ-Fe)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Delta_iron_(δ-Fe)"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.3</span> <span>Delta iron (δ-Fe)</span> </div> </a> <ul id="toc-Delta_iron_(δ-Fe)-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-High_pressure_allotropes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#High_pressure_allotropes"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>High pressure allotropes</span> </div> </a> <button aria-controls="toc-High_pressure_allotropes-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only 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</ul> </li> <li id="toc-Structural_phase_transitions" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Structural_phase_transitions"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Structural phase transitions</span> </div> </a> <ul id="toc-Structural_phase_transitions-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" 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href="https://cs.wikipedia.org/wiki/Alotropick%C3%A9_modifikace_%C5%BEeleza" title="Alotropické modifikace železa – Czech" lang="cs" hreflang="cs" data-title="Alotropické modifikace železa" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Burdin_alotropoak" title="Burdin alotropoak – Basque" lang="eu" hreflang="eu" data-title="Burdin alotropoak" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%AF%DA%AF%D8%B1%D8%B4%DA%A9%D9%84%DB%8C%E2%80%8C%D9%87%D8%A7%DB%8C_%D8%A2%D9%87%D9%86" title="دگرشکلی‌های آهن – Persian" lang="fa" hreflang="fa" data-title="دگرشکلی‌های آهن" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Alotropije_%C5%BEeljeza" title="Alotropije željeza – Croatian" lang="hr" hreflang="hr" data-title="Alotropije željeza" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/Hamskiptarit_j%C3%A1rns" title="Hamskiptarit járns – Icelandic" lang="is" hreflang="is" data-title="Hamskiptarit járns" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Odmiany_alotropowe_%C5%BCelaza" title="Odmiany alotropowe żelaza – Polish" lang="pl" hreflang="pl" data-title="Odmiany alotropowe żelaza" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Allotropes_of_iron" title="Allotropes of iron – Simple English" lang="en-simple" hreflang="en-simple" data-title="Allotropes of iron" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Alotropick%C3%A9_modifik%C3%A1cie_%C5%BEeleza" title="Alotropické modifikácie železa – Slovak" lang="sk" hreflang="sk" data-title="Alotropické modifikácie železa" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%D8%A6%D8%A7%D9%84%DB%86%D8%AA%DA%95%DB%86%D9%BE%DB%8C_%D8%A6%D8%A7%D8%B3%D9%86" title="ئالۆتڕۆپی ئاسن – Central Kurdish" lang="ckb" hreflang="ckb" data-title="ئالۆتڕۆپی ئاسن" data-language-autonym="کوردی" data-language-local-name="Central Kurdish" class="interlanguage-link-target"><span>کوردی</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Alotropije_%C5%BEeljeza" title="Alotropije željeza – Serbo-Croatian" lang="sh" hreflang="sh" data-title="Alotropije željeza" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%90%D0%BB%D0%BE%D1%82%D1%80%D0%BE%D0%BF%D0%B8_%D0%B7%D0%B0%D0%BB%D1%96%D0%B7%D0%B0" title="Алотропи заліза – Ukrainian" lang="uk" hreflang="uk" 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data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Different forms of the element iron</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Pure_iron_phase_diagram_(EN).svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Pure_iron_phase_diagram_%28EN%29.svg/340px-Pure_iron_phase_diagram_%28EN%29.svg.png" decoding="async" width="340" height="302" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Pure_iron_phase_diagram_%28EN%29.svg/510px-Pure_iron_phase_diagram_%28EN%29.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Pure_iron_phase_diagram_%28EN%29.svg/680px-Pure_iron_phase_diagram_%28EN%29.svg.png 2x" data-file-width="675" data-file-height="600" /></a><figcaption>Low-pressure <a href="/wiki/Phase_diagram" title="Phase diagram">phase diagram</a> of pure iron. BCC is <a href="/wiki/Body_centered_cubic" class="mw-redirect" title="Body centered cubic">body centered cubic</a> and FCC is <a href="/wiki/Face-centered_cubic" class="mw-redirect" title="Face-centered cubic">face-centered cubic</a>.</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Iron_carbon_phase_diagram.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Iron_carbon_phase_diagram.svg/390px-Iron_carbon_phase_diagram.svg.png" decoding="async" width="390" height="270" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Iron_carbon_phase_diagram.svg/585px-Iron_carbon_phase_diagram.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Iron_carbon_phase_diagram.svg/780px-Iron_carbon_phase_diagram.svg.png 2x" data-file-width="512" data-file-height="355" /></a><figcaption>Iron-carbon <a href="/wiki/Eutectic_system" title="Eutectic system">eutectic</a> phase diagram, showing various forms of Fe<sub>x</sub>C<sub>y</sub> substances.</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:IronAlfa%26IronGamma.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/IronAlfa%26IronGamma.svg/220px-IronAlfa%26IronGamma.svg.png" decoding="async" width="220" height="110" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/IronAlfa%26IronGamma.svg/330px-IronAlfa%26IronGamma.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/aa/IronAlfa%26IronGamma.svg/440px-IronAlfa%26IronGamma.svg.png 2x" data-file-width="600" data-file-height="300" /></a><figcaption>Iron allotropes, showing the differences in structure. The alpha iron (α-Fe) is a body-centered cubic (BCC) and the gamma iron (γ-Fe) is a face-centered cubic (FCC).</figcaption></figure> <p>At <a href="/wiki/Atmospheric_pressure" title="Atmospheric pressure">atmospheric pressure</a>, three <a href="/wiki/Allotropy" title="Allotropy">allotropic</a> forms of <a href="/wiki/Iron" title="Iron">iron</a> exist, depending on temperature: <a href="/wiki/Ferrite_(iron)" class="mw-redirect" title="Ferrite (iron)">alpha iron (α-Fe, ferrite)</a>, <a href="/wiki/Austenite" title="Austenite">gamma iron (γ-Fe, austenite)</a>, and <a href="/w/index.php?title=Delta_iron_(%CE%B4-Fe)&action=edit&redlink=1" class="new" title="Delta iron (δ-Fe) (page does not exist)">delta iron (δ-Fe)</a>. At very high pressure, a fourth form exists, <a href="/wiki/Hexaferrum" title="Hexaferrum">epsilon iron (ε-Fe, hexaferrum)</a>. Some controversial experimental evidence suggests the existence of a fifth high-pressure form that is stable at very high pressures and temperatures.<sup id="cite_ref-HTP-iron_1-0" class="reference"><a href="#cite_note-HTP-iron-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>The phases of iron at atmospheric pressure are important because of the differences in solubility of <a href="/wiki/Carbon" title="Carbon">carbon</a>, forming different types of <a href="/wiki/Steel" title="Steel">steel</a>. The high-pressure phases of iron are important as models for the solid parts of planetary cores. The <a href="/wiki/Inner_core" class="mw-redirect" title="Inner core">inner core</a> of the <a href="/wiki/Earth" title="Earth">Earth</a> is generally assumed to consist essentially of a crystalline iron-nickel <a href="/wiki/Alloy" title="Alloy">alloy</a> with ε structure.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> The outer core surrounding the solid inner core is believed to be composed of liquid iron mixed with <a href="/wiki/Nickel" title="Nickel">nickel</a> and trace amounts of lighter elements. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Standard_pressure_allotropes">Standard pressure allotropes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=1" title="Edit section: Standard pressure allotropes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Alpha_iron_(α-Fe)"><span id="Alpha_iron_.28.CE.B1-Fe.29"></span>Alpha iron (α-Fe)</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=2" title="Edit section: Alpha iron (α-Fe)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Below 912 °C (1,674 °F), iron has a <a href="/wiki/Body-centered_cubic" class="mw-redirect" title="Body-centered cubic">body-centered cubic</a> (bcc) <a href="/wiki/Crystal" title="Crystal">crystal</a> structure and is known as α-iron or <b>ferrite</b>. It is <a href="/wiki/Chemical_stability" title="Chemical stability">thermodynamically stable</a> and a fairly soft metal. α-Fe can be subjected to pressures up to ca. 15 GPa before transforming into a high-pressure form termed ε-Fe discussed below. </p><p>Magnetically, α-iron is <a href="/wiki/Paramagnetism" title="Paramagnetism">paramagnetic</a> at high temperatures. However, below its <a href="/wiki/Curie_temperature" title="Curie temperature">Curie temperature</a> (<i>T</i><sub>C</sub> or <i>A<sub>2</sub></i>) of 771 °C (1044K or 1420 °F),<sup id="cite_ref-ASM3_5-0" class="reference"><a href="#cite_note-ASM3-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> it becomes <a href="/wiki/Ferromagnetism" title="Ferromagnetism">ferromagnetic</a>. In the past, the paramagnetic form of α-iron was known as <i>beta iron</i> (β-Fe).<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> Even though the slight tetragonal distortion in the ferromagnetic state does constitute a true phase transition, the continuous nature of this transition results in only minor importance in steel <a href="/wiki/Heat_treating" title="Heat treating">heat treating</a>. The A<sub>2</sub> line forms the boundary between the beta iron and alpha fields in the <a href="/wiki/Phase_diagram" title="Phase diagram">phase diagram</a> in Figure 1. </p><p>Similarly, the A<sub>2</sub> boundary is of only minor importance compared to the A<sub>1</sub> (<a href="/wiki/Eutectoid" class="mw-redirect" title="Eutectoid">eutectoid</a>), A<sub>3</sub> and A<sub>cm</sub> critical temperatures. The A<sub>cm</sub>, where <a href="/wiki/Austenite" title="Austenite">austenite</a> is in equilibrium with <a href="/wiki/Cementite" title="Cementite">cementite</a> + γ-Fe, is beyond the right edge in Fig. 1. The α + γ phase field is, technically, the β + γ field above the A<sub>2</sub>. The beta designation maintains continuity of the Greek-letter progression of phases in iron and steel: α-Fe, β-Fe, <a href="/wiki/Austenite" title="Austenite">austenite</a> (γ-Fe), high-temperature δ-Fe, and high-pressure <a href="/wiki/Hexaferrum" title="Hexaferrum">hexaferrum</a> (ε-Fe). </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Iron-alpha-pV.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/88/Iron-alpha-pV.svg/310px-Iron-alpha-pV.svg.png" decoding="async" width="310" height="233" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/88/Iron-alpha-pV.svg/465px-Iron-alpha-pV.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/88/Iron-alpha-pV.svg/620px-Iron-alpha-pV.svg.png 2x" data-file-width="720" data-file-height="540" /></a><figcaption>Molar volume vs. pressure for α-Fe at room temperature.</figcaption></figure> <p>The primary <a href="/wiki/Phase_(matter)" title="Phase (matter)">phase</a> of low-carbon or <a href="/wiki/Mild_steel" class="mw-redirect" title="Mild steel">mild steel</a> and most <a href="/wiki/Cast_iron" title="Cast iron">cast irons</a> at room temperature is <a href="/wiki/Ferromagnetic" class="mw-redirect" title="Ferromagnetic">ferromagnetic</a> α-Fe.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> It has a hardness of approximately 80 <a href="/wiki/Brinell_scale" title="Brinell scale">Brinell</a>.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Alvarenga_11-0" class="reference"><a href="#cite_note-Alvarenga-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> The maximum <a href="/wiki/Solubility" title="Solubility">solubility</a> of carbon is about 0.02 wt% at 727 °C (1,341 °F) and 0.001% at 0 °C (32 °F).<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> When it dissolves in iron, carbon atoms occupy interstitial "holes". Being about twice the diameter of the <a href="/wiki/Tetrahedral_hole" class="mw-redirect" title="Tetrahedral hole">tetrahedral hole</a>, the carbon introduces a strong local strain field. </p><p><a href="/wiki/Mild_steel" class="mw-redirect" title="Mild steel">Mild steel</a> (carbon steel with up to about 0.2 wt% C) consists mostly of α-Fe and increasing amounts of <a href="/wiki/Cementite" title="Cementite">cementite</a> (Fe<sub>3</sub>C, an iron carbide). The mixture adopts a lamellar structure called <a href="/wiki/Pearlite" title="Pearlite">pearlite</a>. Since <a href="/wiki/Bainite" title="Bainite">bainite</a> and pearlite each contain α-Fe as a component, any iron-carbon alloy will contain some amount of α-Fe if it is allowed to reach <a href="/wiki/Chemical_equilibrium" title="Chemical equilibrium">equilibrium</a> at room temperature. The amount of α-Fe depends on the cooling process. </p> <div class="mw-heading mw-heading4"><h4 id="A2_critical_temperature_and_induction_heating">A<sub>2</sub> critical temperature and induction heating</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=3" title="Edit section: A2 critical temperature and induction heating"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Beta_iron_carbon_pd.TIF" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/2f/Beta_iron_carbon_pd.TIF/lossy-page1-290px-Beta_iron_carbon_pd.TIF.jpg" decoding="async" width="290" height="172" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2f/Beta_iron_carbon_pd.TIF/lossy-page1-435px-Beta_iron_carbon_pd.TIF.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/2f/Beta_iron_carbon_pd.TIF/lossy-page1-580px-Beta_iron_carbon_pd.TIF.jpg 2x" data-file-width="815" data-file-height="482" /></a><figcaption><b>Figure 1:</b> The beta field and A<sub>2</sub> critical temperature on the iron-rich side of the iron-carbon phase diagram.<sup id="cite_ref-ASM3_5-1" class="reference"><a href="#cite_note-ASM3-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup></figcaption></figure><p>β-Fe and the A<sub>2</sub> critical temperature are important in <a href="/wiki/Induction_heating" title="Induction heating">induction heating</a> of steel, such as for surface-hardening heat treatments. Steel is typically austenitized at 900–1000 °C before it is <a href="/wiki/Quenching" title="Quenching">quenched</a> and <a href="/wiki/Tempering_(metallurgy)" title="Tempering (metallurgy)">tempered</a>. The high-frequency alternating magnetic field of induction heating heats the steel by two mechanisms below the Curie temperature: resistance or <a href="/wiki/Joule_heating" title="Joule heating">Joule heating</a> and ferromagnetic <a href="/wiki/Hysteresis#In_materials" title="Hysteresis">hysteresis</a> losses. Above the A<sub>2</sub> boundary, the hysteresis mechanism disappears and the required amount of energy per degree of temperature increase is thus substantially larger than below A<sub>2</sub>. Load-matching circuits may be needed to vary the <a href="/wiki/Electrical_impedance" title="Electrical impedance">impedance</a> in the induction power source to compensate for the change.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </p><div class="mw-heading mw-heading3"><h3 id="Gamma_iron_(γ-Fe)"><span id="Gamma_iron_.28.CE.B3-Fe.29"></span>Gamma iron (γ-Fe)</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=4" title="Edit section: Gamma iron (γ-Fe)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Austenite" title="Austenite">Austenite</a></div> <p>When heating iron above 912 °C (1,674 °F), its <a href="/wiki/Crystal_structure" title="Crystal structure">crystal structure</a> changes to a <a href="/wiki/Face-centered_cubic" class="mw-redirect" title="Face-centered cubic">face-centered cubic</a> (fcc) crystalline structure. In this form it is called gamma iron (γ-Fe) or <a href="/wiki/Austenite" title="Austenite">austenite</a>. γ-iron can dissolve considerably more carbon (as much as 2.04% by mass at 1,146 °C). This γ form of carbon saturation is exhibited in <a href="/wiki/Austenitic_stainless_steel" title="Austenitic stainless steel">austenitic stainless steel</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Delta_iron_(δ-Fe)"><span id="Delta_iron_.28.CE.B4-Fe.29"></span>Delta iron (δ-Fe)</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=5" title="Edit section: Delta iron (δ-Fe)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Peculiarly, above 1,394 °C (2,541 °F), iron changes back into the bcc structure, known as δ-Fe.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> δ-iron can dissolve as much as 0.08% of carbon by mass at 1,475 °C. It is stable up to its melting point of 1,538 °C (2,800 °F). δ-Fe cannot exist above 5.2 GPa, with austenite instead transitioning directly to a molten phase at these high pressures.<sup id="cite_ref-:0_15-0" class="reference"><a href="#cite_note-:0-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="High_pressure_allotropes">High pressure allotropes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=6" title="Edit section: High pressure allotropes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Epsilon_iron_/_Hexaferrum_(ε-Fe)"><span id="Epsilon_iron_.2F_Hexaferrum_.28.CE.B5-Fe.29"></span>Epsilon iron / Hexaferrum (ε-Fe)</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=7" title="Edit section: Epsilon iron / Hexaferrum (ε-Fe)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Hexaferrum" title="Hexaferrum">Hexaferrum</a></div> <p>At pressures above approximately 10-13 GPa and temperatures up to around 700 K, α-iron changes into a <a href="/wiki/Hexagonal_close-packed" class="mw-redirect" title="Hexagonal close-packed">hexagonal close-packed</a> (hcp) structure, which is also known as ε-iron or hexaferrum;<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> the higher-temperature γ-phase also changes into ε-iron, but generally requires far higher pressures as temperature increases. The <a href="/wiki/Triple_point" title="Triple point">triple point</a> of hexaferrum, ferrite, and austenite is 10.5 GPa at 750 K.<sup id="cite_ref-:0_15-1" class="reference"><a href="#cite_note-:0-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Antiferromagnetism" title="Antiferromagnetism">Antiferromagnetism</a> in alloys of epsilon-Fe with Mn, Os and Ru has been observed.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Experimental_high_temperature_and_pressure">Experimental high temperature and pressure</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=8" title="Edit section: Experimental high temperature and pressure"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>An alternate stable form, if it exists, may appear at pressures of at least 50 GPa and temperatures of at least 1,500 K; it has been thought to have an <a href="/wiki/Orthorhombic" class="mw-redirect" title="Orthorhombic">orthorhombic</a> or a double hcp structure.<sup id="cite_ref-HTP-iron_1-1" class="reference"><a href="#cite_note-HTP-iron-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> As of December 2011<sup class="plainlinks noexcerpt noprint asof-tag update" style="display:none;"><a class="external text" href="https://en.wikipedia.org/w/index.php?title=Allotropes_of_iron&action=edit">[update]</a></sup>, recent and ongoing experiments are being conducted on high-pressure and <a href="/wiki/Superdense_carbon_allotropes" title="Superdense carbon allotropes">superdense carbon allotropes</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Phase_transitions">Phase transitions</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=9" title="Edit section: Phase transitions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Melting_and_boiling_points">Melting and boiling points</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=10" title="Edit section: Melting and boiling points"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The melting point of iron is experimentally well defined for pressures less than 50 GPa. </p><p>For greater pressures, published data (as of 2007) put the γ-ε-liquid <a href="/wiki/Triple_point" title="Triple point">triple point</a> at pressures that differ by tens of gigapascals and 1000 K in the melting point. Generally speaking, <a href="/wiki/Molecular_dynamics" title="Molecular dynamics">molecular dynamics</a> computer simulations of iron melting and shock wave experiments suggest higher melting points and a much steeper slope of the melting curve than static experiments carried out in <a href="/wiki/Diamond_anvil_cell" title="Diamond anvil cell">diamond anvil cells</a>.<sup id="cite_ref-melting_18-0" class="reference"><a href="#cite_note-melting-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> </p><p>The melting and boiling points of iron, along with its <a href="/wiki/Enthalpy_of_atomization" title="Enthalpy of atomization">enthalpy of atomization</a>, are lower than those of the earlier group 3d elements from <a href="/wiki/Scandium" title="Scandium">scandium</a> to <a href="/wiki/Chromium" title="Chromium">chromium</a>, showing the lessened contribution of the <a href="/wiki/Electron_shell_configuration" class="mw-redirect" title="Electron shell configuration">3d electrons</a> to metallic bonding as they are attracted more and more into the inert core by the <a href="/wiki/Atomic_nucleus" title="Atomic nucleus">nucleus</a>;<sup id="cite_ref-Greenwood1116_19-0" class="reference"><a href="#cite_note-Greenwood1116-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> however, they are higher than the values for the previous element <a href="/wiki/Manganese" title="Manganese">manganese</a> because that element has a half-filled 3d subshell and consequently its d-electrons are not easily <a href="/wiki/Delocalized_electron" title="Delocalized electron">delocalized</a>. This same trend appears for <a href="/wiki/Ruthenium" title="Ruthenium">ruthenium</a> but not <a href="/wiki/Osmium" title="Osmium">osmium</a>.<sup id="cite_ref-Greenwood1074_20-0" class="reference"><a href="#cite_note-Greenwood1074-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Structural_phase_transitions">Structural phase transitions</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=11" title="Edit section: Structural phase transitions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">"Gamma loop" redirects here. Not to be confused with <a href="/wiki/Gamma_motor_neuron" title="Gamma motor neuron">Gamma motor neuron</a>.</div> <p>The exact temperatures at which iron will transition from one crystal structure to another depends on how much and what type of other elements are dissolved in the iron. The phase boundary between the different solid phases is drawn on a <a href="/wiki/Phase_diagram#Binary_mixtures" title="Phase diagram">binary phase diagram</a>, usually plotted as temperature versus percent iron. Adding some elements, such as <a href="/wiki/Chromium" title="Chromium">Chromium</a>, narrows the temperature range for the gamma phase, while others increase the temperature range of the gamma phase. In elements that reduce the gamma phase range, the alpha-gamma phase boundary connects with the gamma-delta phase boundary, forming what is usually called the <i>Gamma loop</i>. Adding Gamma loop additives keeps the iron in a body-centered cubic structure and prevents the steel from suffering <a href="/wiki/Phase_transition" title="Phase transition">phase transition</a> to other solid states.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=12" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Tempering_(metallurgy)" title="Tempering (metallurgy)">Tempering (metallurgy)</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Allotropes_of_iron&action=edit&section=13" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width reflist-columns-2"> <ol class="references"> <li id="cite_note-HTP-iron-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-HTP-iron_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-HTP-iron_1-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFBoehler2000" class="citation journal cs1">Boehler, Reinhard (2000). <a rel="nofollow" class="external text" href="https://doi.org/10.1029%2F1998RG000053">"High-pressure experiments and the phase diagram of lower mantle and core materials"</a>. <i>Reviews of Geophysics</i>. <b>38</b> (2). American Geophysical Union: 221–245. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2000RvGeo..38..221B">2000RvGeo..38..221B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1029%2F1998RG000053">10.1029/1998RG000053</a></span>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:33458168">33458168</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Reviews+of+Geophysics&rft.atitle=High-pressure+experiments+and+the+phase+diagram+of+lower+mantle+and+core+materials&rft.volume=38&rft.issue=2&rft.pages=221-245&rft.date=2000&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A33458168%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1029%2F1998RG000053&rft_id=info%3Abibcode%2F2000RvGeo..38..221B&rft.aulast=Boehler&rft.aufirst=Reinhard&rft_id=https%3A%2F%2Fdoi.org%2F10.1029%252F1998RG000053&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAllotropes+of+iron" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCohenStixrude,_Lars" class="citation web cs1">Cohen, Ronald E.; Stixrude, Lars. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20070205041442/http://www.psc.edu/science/Cohen_Stix/cohen_stix.html">"Crystal at the Center of the Earth"</a>. Archived from <a rel="nofollow" class="external text" href="http://www.psc.edu/science/Cohen_Stix/cohen_stix.html">the original</a> on 5 February 2007<span class="reference-accessdate">. Retrieved <span class="nowrap">2007-02-05</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Crystal+at+the+Center+of+the+Earth&rft.aulast=Cohen&rft.aufirst=Ronald+E.&rft.au=Stixrude%2C+Lars&rft_id=http%3A%2F%2Fwww.psc.edu%2Fscience%2FCohen_Stix%2Fcohen_stix.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAllotropes+of+iron" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStixrudeCohen1995" class="citation journal cs1">Stixrude, Lars; Cohen, Ronald E. (March 1995). "High-Pressure Elasticity of Iron and Anisotropy of Earth's Inner Core". <i>Science</i>. <b>267</b> (5206): 1972–5. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1995Sci...267.1972S">1995Sci...267.1972S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.267.5206.1972">10.1126/science.267.5206.1972</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/17770110">17770110</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:39711239">39711239</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=High-Pressure+Elasticity+of+Iron+and+Anisotropy+of+Earth%27s+Inner+Core&rft.volume=267&rft.issue=5206&rft.pages=1972-5&rft.date=1995-03&rft_id=info%3Adoi%2F10.1126%2Fscience.267.5206.1972&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A39711239%23id-name%3DS2CID&rft_id=info%3Apmid%2F17770110&rft_id=info%3Abibcode%2F1995Sci...267.1972S&rft.aulast=Stixrude&rft.aufirst=Lars&rft.au=Cohen%2C+Ronald+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAllotropes+of+iron" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.bbc.co.uk/news/uk-14678004">"What is at the centre of the Earth?"</a>. <i>BBC News</i>. 31 August 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=BBC+News&rft.atitle=What+is+at+the+centre+of+the+Earth%3F&rft.date=2011-08-31&rft_id=https%3A%2F%2Fwww.bbc.co.uk%2Fnews%2Fuk-14678004&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAllotropes+of+iron" class="Z3988"></span></span> </li> <li id="cite_note-ASM3-5"><span class="mw-cite-backlink">^ <a href="#cite_ref-ASM3_5-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-ASM3_5-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation book cs1"><i>Alloy Phase Diagrams</i>. ASM Handbook. Vol. 3. ASM International. 1992. pp. 2.210, 4.9. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-87170-381-1" title="Special:BookSources/978-0-87170-381-1"><bdi>978-0-87170-381-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Alloy+Phase+Diagrams&rft.series=ASM+Handbook&rft.pages=2.210%2C+4.9&rft.pub=ASM+International&rft.date=1992&rft.isbn=978-0-87170-381-1&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAllotropes+of+iron" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text">Bullens, Denison Kingsley, <i>Steel and its Heat Treatment</i>, Vol. I, Fourth Ed., J. 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ASM International. pp. 95–98. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-87170-211-1" title="Special:BookSources/978-0-87170-211-1"><bdi>978-0-87170-211-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Induction+Heat+Treatment+of+Steel&rft.pages=95-98&rft.pub=ASM+International&rft.date=1986&rft.isbn=978-0-87170-211-1&rft.aulast=Semiatin&rft.aufirst=S.+Lee&rft.au=Stutz%2C+David+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAllotropes+of+iron" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLyman1973" class="citation book cs1">Lyman, Taylor, ed. (1973). <i>Metallography, Structures and Phase Diagrams</i>. Metals Handbook. 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Paul; Polian, Alain; d'Astuto, Matteo; Chervin, Jean-Claude; Pascarelli, Sakura (14 December 2004). "Dynamics of the magnetic and structural alpha-epsilon phase transition in iron". <i>Physical Review Letters</i>. <b>93</b> (25): 255503. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/cond-mat/0405439">cond-mat/0405439</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2004PhRvL..93y5503M">2004PhRvL..93y5503M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRevLett.93.255503">10.1103/PhysRevLett.93.255503</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/15697906">15697906</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:19228886">19228886</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physical+Review+Letters&rft.atitle=Dynamics+of+the+magnetic+and+structural+alpha-epsilon+phase+transition+in+iron&rft.volume=93&rft.issue=25&rft.pages=255503&rft.date=2004-12-14&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A19228886%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2004PhRvL..93y5503M&rft_id=info%3Aarxiv%2Fcond-mat%2F0405439&rft_id=info%3Apmid%2F15697906&rft_id=info%3Adoi%2F10.1103%2FPhysRevLett.93.255503&rft.au=Mathon%2C+Olivier&rft.au=Baudelet%2C+Fran%C3%A7ois&rft.au=Iti%C3%A9%2C+J.+Paul&rft.au=Polian%2C+Alain&rft.au=d%27Astuto%2C+Matteo&rft.au=Chervin%2C+Jean-Claude&rft.au=Pascarelli%2C+Sakura&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAllotropes+of+iron" class="Z3988"></span></span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFletcher,_Geoffrey_C.Addis,_Robert_P.1974" class="citation journal cs1">Fletcher, Geoffrey C.; Addis, Robert P. (November 1974). <a rel="nofollow" class="external text" href="http://iopscience.iop.org/0305-4608/4/11/020/pdf/0305-4608_4_11_020.pdf">"The magnetic state of the phase of iron"</a> <span class="cs1-format">(PDF)</span>. <i>Journal of Physics F: Metal Physics</i>. <b>4</b> (11): 1954. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1974JPhF....4.1951F">1974JPhF....4.1951F</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1088%2F0305-4608%2F4%2F11%2F020">10.1088/0305-4608/4/11/020</a><span class="reference-accessdate">. Retrieved <span class="nowrap">December 30,</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Physics+F%3A+Metal+Physics&rft.atitle=The+magnetic+state+of+the+phase+of+iron&rft.volume=4&rft.issue=11&rft.pages=1954&rft.date=1974-11&rft_id=info%3Adoi%2F10.1088%2F0305-4608%2F4%2F11%2F020&rft_id=info%3Abibcode%2F1974JPhF....4.1951F&rft.au=Fletcher%2C+Geoffrey+C.&rft.au=Addis%2C+Robert+P.&rft_id=http%3A%2F%2Fiopscience.iop.org%2F0305-4608%2F4%2F11%2F020%2Fpdf%2F0305-4608_4_11_020.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAllotropes+of+iron" class="Z3988"></span></span> </li> <li id="cite_note-melting-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-melting_18-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBoehlerRoss2007" class="citation book cs1">Boehler, Reinhard; Ross, M. (2007). "Properties of Rocks and Minerals_High-Pressure Melting". <i>Mineral Physics</i>. Treatise on Geophysics. Vol. 2. Elsevier. pp. 527–41. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2FB978-044452748-6.00047-X">10.1016/B978-044452748-6.00047-X</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-444-52748-6" title="Special:BookSources/978-0-444-52748-6"><bdi>978-0-444-52748-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Properties+of+Rocks+and+Minerals_High-Pressure+Melting&rft.btitle=Mineral+Physics&rft.series=Treatise+on+Geophysics&rft.pages=527-41&rft.pub=Elsevier&rft.date=2007&rft_id=info%3Adoi%2F10.1016%2FB978-044452748-6.00047-X&rft.isbn=978-0-444-52748-6&rft.aulast=Boehler&rft.aufirst=Reinhard&rft.au=Ross%2C+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAllotropes+of+iron" class="Z3988"></span></span> </li> <li id="cite_note-Greenwood1116-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-Greenwood1116_19-0">^</a></b></span> <span class="reference-text">Greenwood and Earnshaw, p. 1116</span> </li> <li id="cite_note-Greenwood1074-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-Greenwood1074_20-0">^</a></b></span> <span class="reference-text">Greenwood and Earnshaw, pp. 1074–75</span> </li> <li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKutz,_Myer2002" class="citation book cs1">Kutz, Myer, ed. (2002-07-22). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=gWg-rchM700C&q=gamma+loop+steel+-medicine+-medical&pg=PA44"><i>Handbook of Materials Selection</i></a>. p. 44. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-471-35924-1" title="Special:BookSources/978-0-471-35924-1"><bdi>978-0-471-35924-1</bdi></a><span class="reference-accessdate">. Retrieved <span class="nowrap">December 19,</span> 2013</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Handbook+of+Materials+Selection&rft.pages=44&rft.date=2002-07-22&rft.isbn=978-0-471-35924-1&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DgWg-rchM700C%26q%3Dgamma%2Bloop%2Bsteel%2B-medicine%2B-medical%26pg%3DPA44&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAllotropes+of+iron" class="Z3988"></span></span> </li> </ol></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Allotropes_of_iron&oldid=1250191053">https://en.wikipedia.org/w/index.php?title=Allotropes_of_iron&oldid=1250191053</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Allotropes" title="Category:Allotropes">Allotropes</a></li><li><a href="/wiki/Category:Iron" title="Category:Iron">Iron</a></li><li><a href="/wiki/Category:Metallurgy" title="Category:Metallurgy">Metallurgy</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_is_different_from_Wikidata" title="Category:Short description is different from Wikidata">Short description is different from Wikidata</a></li><li><a href="/wiki/Category:Articles_containing_potentially_dated_statements_from_December_2011" title="Category:Articles containing potentially dated statements from December 2011">Articles containing potentially dated statements from December 2011</a></li><li><a href="/wiki/Category:All_articles_containing_potentially_dated_statements" title="Category:All articles containing potentially dated statements">All articles containing potentially dated statements</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 9 October 2024, at 00:31<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. 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