{"id":17712,"date":"2026-04-09T20:56:48","date_gmt":"2026-04-09T15:26:48","guid":{"rendered":"https:\/\/aluminiummagazine.com\/mag\/?p=17712"},"modified":"2026-04-16T18:54:38","modified_gmt":"2026-04-16T13:24:38","slug":"aluminium-7475-aluminum-7475-alloy-properties-aerospace-guide","status":"publish","type":"post","link":"https:\/\/aluminiummagazine.com\/mag\/aluminium\/aluminium-7475-aluminum-7475-alloy-properties-aerospace-guide.html","title":{"rendered":"Aluminium 7475: The Second-Generation Aerospace Alloy for Superior Fracture Toughness"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"><strong>Aluminium 7475 \u2013 also known as Aluminum 7475 \u2013 is a heat-treatable aluminium-zinc-magnesium-copper alloy that represents the second generation of the 7000 series. Developed by Alcoa and registered in 1969 as a controlled\u2011toughness alloy, 7475 aluminum offers a fracture toughness approximately 40% greater than the industry\u2011standard 7075 while maintaining comparable high strength. It is the material of choice for fracture\u2011critical aerospace components, including fuselage skins, wing skins, and structural parts where crack propagation resistance is a paramount design consideration.<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<div style=\"height:75px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>What is Aluminium 7475?<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Aluminium alloy 7475 is a member of the <strong>7000 series<\/strong> (aluminium\u2011zinc\u2011magnesium\u2011copper) alloys \u2013 the strongest family of aluminium alloys widely used in aerospace. Unlike the non\u2011heat\u2011treatable 5000 series alloys covered earlier, 7475 is a <strong>heat\u2011treatable<\/strong> alloy that achieves its outstanding mechanical properties through controlled thermal processing.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Within the 7000 series, if <strong>7075<\/strong> is regarded as the first generation, <strong>7475<\/strong> \u2013 registered in September 1969 \u2013 is considered the second generation, alongside 7175. Its defining characteristic is <strong>controlled fracture toughness<\/strong>: while offering strength comparable to 7075, 7475 provides significantly better resistance to crack propagation. This makes it indispensable for components that must remain safe even if a crack initiates in service.<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Key Characteristics at a Glance:<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-center\" data-align=\"center\">Property<\/th><th class=\"has-text-align-center\" data-align=\"center\">Value<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-center\" data-align=\"center\">Density<\/td><td class=\"has-text-align-center\" data-align=\"center\">2.81 g\/cm\u00b3<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Melting Point<\/td><td class=\"has-text-align-center\" data-align=\"center\">477 \u2013 546 \u00b0C<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Thermal Conductivity<\/td><td class=\"has-text-align-center\" data-align=\"center\">177 W\/m\u00b7K<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Modulus of Elasticity<\/td><td class=\"has-text-align-center\" data-align=\"center\">71.7 GPa<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Electrical Resistivity<\/td><td class=\"has-text-align-center\" data-align=\"center\">4.99 \u00d7 10\u207b\u2076 ohm\u00b7cm<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Data compiled from industry specifications<\/em><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Chemical Composition of Aluminium 7475<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Aluminium 7475 is a zinc\u2011rich alloy with carefully balanced additions of magnesium, copper, and chromium. The <strong>copper content (1.2\u20131.9%)<\/strong> is a key difference from earlier 7000 series alloys, enhancing strength and stress\u2011corrosion resistance. The <strong>low silicon and iron limits<\/strong> (\u22640.10% and \u22640.12% respectively) contribute to the alloy\u2019s excellent fracture toughness by minimising coarse, brittle intermetallic particles.<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-center\" data-align=\"center\">Element<\/th><th class=\"has-text-align-center\" data-align=\"center\">Percentage (%)<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-center\" data-align=\"center\">Aluminum (Al)<\/td><td class=\"has-text-align-center\" data-align=\"center\">88.5 \u2013 91.5<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Zinc (Zn)<\/td><td class=\"has-text-align-center\" data-align=\"center\">5.2 \u2013 6.2<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Magnesium (Mg)<\/td><td class=\"has-text-align-center\" data-align=\"center\">1.9 \u2013 2.6<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Copper (Cu)<\/td><td class=\"has-text-align-center\" data-align=\"center\">1.2 \u2013 1.9<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Chromium (Cr)<\/td><td class=\"has-text-align-center\" data-align=\"center\">0.18 \u2013 0.25<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Silicon (Si)<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u22640.10<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Iron (Fe)<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u22640.12<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Manganese (Mn)<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u22640.06<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Titanium (Ti)<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u22640.06<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Others (Each)<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u22640.05<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">Others (Total)<\/td><td class=\"has-text-align-center\" data-align=\"center\">\u22640.15<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Source: ASM \/ Aluminum Association<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>zinc and magnesium<\/strong> form fine strengthening precipitates (MgZn\u2082) during artificial aging. The <strong>copper<\/strong> provides additional solid\u2011solution strengthening and improves stress\u2011corrosion cracking resistance. The <strong>chromium<\/strong> acts as a recrystallisation inhibitor, helping to maintain a fine, unrecrystallised grain structure that is essential for high toughness.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<div style=\"height:75px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Key Properties of Aluminium 7475<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udcaa Exceptional Strength \u2013 Comparable to 7075<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Aluminium 7475 delivers very high strength, comparable to the widely used 7075 alloy. In the T651 temper, typical values are:<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Ultimate Tensile Strength:<\/strong> 586 MPa (85,000 psi)<\/li>\n\n\n\n<li><strong>Tensile Yield Strength:<\/strong> 510 MPa (74,000 psi)<\/li>\n\n\n\n<li><strong>Elongation at Break:<\/strong> 13%<\/li>\n\n\n\n<li><strong>Hardness (Brinell):<\/strong> 150 HB<\/li>\n\n\n\n<li><strong>Shear Strength:<\/strong> 350 MPa (50,800 psi)<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Source: ASM Material Data Sheet<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">These values place 7475 among the strongest aluminium alloys commercially available, exceeded only by specialised alloys such as 7055 and 7068 in certain tempers.<\/p>\n\n\n\n<div style=\"height:50px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83e\udde0 Superior Fracture Toughness \u2013 The Defining Advantage<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">This is where <strong>Aluminium 7475 truly excels<\/strong>. Compared to 7075 in the same temper, 7475 aluminium sheet and plate typically offer a <strong>40% increase in toughness<\/strong>. This remarkable improvement is achieved through strict control of composition (especially low Fe and Si) and thermo\u2011mechanical processing that produces a fine, unrecrystallised grain structure.<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Fracture toughness values for 7475 plate (T\u2011L orientation):<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Property<\/th><th>Value<\/th><\/tr><\/thead><tbody><tr><td>Fracture Toughness (L\u2011T)<\/td><td>42.9 MPa\u00b7\u221am<\/td><\/tr><tr><td>Fracture Toughness (T\u2011L)<\/td><td>37.4 MPa\u00b7\u221am<\/td><\/tr><tr><td>Fracture Toughness (S\u2011L)<\/td><td>29.7 MPa\u00b7\u221am<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Source: MatWeb<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For aerospace designers, this combination of high strength and high fracture toughness means that 7475 can be used in <strong>damage\u2011tolerant designs<\/strong> \u2013 components that can safely sustain cracks without catastrophic failure.<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udca4 Excellent Fatigue Resistance<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">7475 aluminium exhibits good fatigue crack propagation resistance, often outperforming other high\u2011strength aluminium alloys. This is particularly important for components subjected to cyclic loading, such as aircraft wing skins and fuselage panels. The alloy\u2019s resistance to fatigue crack growth is one of the reasons it is specified for fracture\u2011critical applications.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udee1\ufe0f Corrosion Resistance<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The corrosion resistance of 7475 is <strong>comparable to that of 7075<\/strong>, which is considered good for a high\u2011strength 7000 series alloy. However, like most 7xxx alloys, 7475 is susceptible to stress\u2011corrosion cracking (SCC) in certain tempers and orientations. For this reason, aerospace specifications often require overaged tempers (T7351, T7651) that provide the best resistance to SCC.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u2699\ufe0f High Machinability<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Aluminium 7475 has <strong>good machining characteristics<\/strong>, with a machinability rating of 70% on a 0\u2011100 scale where 100% represents free\u2011machining alloy 2011. The alloy machines best in the annealed condition; oil\u2011based lubricants are recommended during machining operations.<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udd27 Formability<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">7475 can be formed using conventional methods, but with an important caveat: it is <strong>much easier to form in the annealed condition<\/strong>. In the heat\u2011treated condition, the alloy exhibits <strong>significant springback<\/strong> due to its high strength. For complex forming operations, the material should be formed in the annealed (O) temper, then subsequently heat treated to achieve final mechanical properties.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udeab Weldability \u2013 A Critical Limitation<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Aluminium 7475 is not weldable by conventional fusion welding methods.<\/strong> This is a direct consequence of its high zinc and copper content, which makes the alloy highly susceptible to hot cracking during welding. For this reason, aerospace components made from 7475 are typically joined using <strong>mechanical fasteners<\/strong> (rivets, bolts) or adhesive bonding, rather than welding.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udd25 Heat Treatment<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Unlike the 5000 series alloys, <strong>Aluminium 7475 is heat treatable<\/strong>. This is the primary mechanism by which its exceptional mechanical properties are achieved. The typical heat treatment sequence is:<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Solution heat treatment<\/strong> \u2013 heating to approximately 465\u2013480\u00b0C to dissolve alloying elements<\/li>\n\n\n\n<li><strong>Quenching<\/strong> \u2013 rapid cooling (usually in water) to retain the dissolved elements in supersaturated solid solution<\/li>\n\n\n\n<li><strong>Artificial aging<\/strong> \u2013 controlled heating (typically 120\u2013175\u00b0C) to precipitate fine strengthening particles<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">Common tempers for 7475 include:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-center\" data-align=\"center\">Temper<\/th><th>Description<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>O<\/strong><\/td><td>Annealed \u2013 maximum formability, minimum strength<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>T6<\/strong><\/td><td>Solution treated and artificially aged \u2013 maximum strength<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>T651<\/strong><\/td><td>Solution treated, stress\u2011relieved by stretching, then artificially aged<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>T7351<\/strong><\/td><td>Overaged for maximum stress\u2011corrosion cracking resistance<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>T761<\/strong><\/td><td>A special temper with optimised toughness and corrosion resistance<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>T7651<\/strong><\/td><td>Solution treated, stress\u2011relieved, and overaged<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<div style=\"height:75px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Applications of Aluminium 7475<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Aluminium 7475 is a <strong>premium aerospace alloy<\/strong> whose unique combination of high strength and superior fracture toughness makes it essential for safety\u2011critical components where failure is not an option.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u2708\ufe0f Aerospace &amp; Aviation \u2013 <em>The Primary Application<\/em><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">7475 aluminium is widely used in commercial and military aircraft for components where fracture toughness is a major design consideration:<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Fuselage skins<\/strong> \u2013 particularly in pressurised areas where crack propagation must be controlled<\/li>\n\n\n\n<li><strong>Wing skins<\/strong> \u2013 both upper and lower surfaces requiring a combination of strength and damage tolerance<\/li>\n\n\n\n<li><strong>Fracture\u2011critical structural parts<\/strong> \u2013 components whose failure would lead to catastrophic loss of the aircraft<\/li>\n\n\n\n<li><strong>Bulkheads and frames<\/strong> \u2013 where high strength and resistance to crack growth are essential<\/li>\n\n\n\n<li><strong>Floor beams and cargo bay structures<\/strong><\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udd2b Defence &amp; Military Applications<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Shell casings<\/strong> \u2013 7475 is specified for certain ammunition components<\/li>\n\n\n\n<li><strong>Missile airframes<\/strong> \u2013 where weight reduction and structural integrity are critical<\/li>\n\n\n\n<li><strong>Armoured vehicle components<\/strong> \u2013 where a combination of strength and toughness is required<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83c\udfce\ufe0f High\u2011Performance Automotive<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">While less common than in aerospace, 7475 is sometimes used in:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Racing car chassis components<\/strong> \u2013 where weight, strength, and toughness are all at a premium<\/li>\n\n\n\n<li><strong>High\u2011performance suspension components<\/strong><\/li>\n\n\n\n<li><strong>Safety\u2011critical automotive structures<\/strong><\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<div style=\"height:75px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Aluminium 7475 vs. Aluminium 7075<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The comparison between <strong>7475<\/strong> and <strong>7075<\/strong> is the most important one for engineers choosing a high\u2011strength 7000 series alloy. Rather than presenting a dense table, here is a practical guide:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-center\" data-align=\"center\">Aspect<\/th><th>7475<\/th><th>7075<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Tensile Strength<\/strong><\/td><td>Comparable (\u2248586 MPa in T651)<\/td><td>Comparable (\u2248570\u2011590 MPa)<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Fracture Toughness<\/strong><\/td><td>Approximately <strong>40% higher<\/strong> \u2013 the defining advantage<\/td><td>Good, but significantly lower<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Fatigue Crack Growth Resistance<\/strong><\/td><td>Superior \u2013 better resistance to crack propagation<\/td><td>Good<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Corrosion Resistance<\/strong><\/td><td>Comparable (good; overaged tempers for SCC resistance)<\/td><td>Comparable<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Machinability<\/strong><\/td><td>70% \u2013 very good<\/td><td>70\u201180% \u2013 excellent<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Weldability<\/strong><\/td><td><strong>Not weldable<\/strong> \u2013 must use mechanical fasteners<\/td><td>Very poor \u2013 generally not welded<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Cost<\/strong><\/td><td>Higher \u2013 due to tighter composition and process control<\/td><td>Lower \u2013 the industry standard<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Availability<\/strong><\/td><td>Readily available, but less common than 7075<\/td><td>Widely available<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Primary Use<\/strong><\/td><td><strong>Fracture\u2011critical aerospace components<\/strong><\/td><td>General high\u2011strength applications<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\"><strong>Pro Tip:<\/strong> Choose <strong>7475<\/strong> when your design is <strong>fracture\u2011critical<\/strong> \u2013 that is, when a crack must be able to grow stably without causing sudden failure. Choose <strong>7075<\/strong> when cost is a primary driver and the component can tolerate lower fracture toughness. For applications requiring the highest possible strength with good weldability, consider 7005 or 7039 instead.<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">For a detailed, interactive side\u2011by\u2011side comparison of 7475 with any other aluminium alloy \u2013 including 7075, 2024, 6061, or 5083 \u2013 visit the <strong><a href=\"https:\/\/aluminiummagazine.com\/webtools\/alloy-comparison-tool.html\">Aluminium Alloy Comparison Tool<\/a><\/strong>. This tool allows you to compare over 40 alloy types across properties including strength, fracture toughness, weldability, and corrosion resistance.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<div style=\"height:75px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Fabrication &amp; Workability Guide<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udd28 Forming<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Aluminium 7475 can be formed using conventional methods, but it is <strong>much easier to form in the annealed (O) condition<\/strong>. In the heat\u2011treated condition, the alloy has more springback because of its high strength. For complex forming operations, follow this sequence:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Form in the <strong>O (annealed) temper<\/strong><\/li>\n\n\n\n<li>Solution heat treat and quench<\/li>\n\n\n\n<li>Perform any necessary straightening<\/li>\n\n\n\n<li>Artificially age to final temper<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">\u2699\ufe0f Machining<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Aluminium 7475 has <strong>good machining characteristics<\/strong> (70% machinability rating). Best practices include:<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Machine in the <strong>annealed condition<\/strong> for optimal results<\/li>\n\n\n\n<li>Use <strong>oil\u2011based lubricants<\/strong> to ensure proper chip evacuation and surface finish<\/li>\n\n\n\n<li>Employ <strong>carbide\u2011tipped tools<\/strong> with sharp edges<\/li>\n\n\n\n<li>Apply <strong>positive rake angles<\/strong> to minimise cutting forces<\/li>\n\n\n\n<li>Use <strong>high cutting speeds<\/strong> to reduce built\u2011up edge formation<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udd25 Heat Treatment<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">As a heat\u2011treatable alloy, 7475 can be significantly strengthened by thermal processing:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-center\" data-align=\"center\">Process<\/th><th>Typical Parameters<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Solution Treatment<\/strong><\/td><td>465\u2011480\u00b0C, hold for sufficient time to dissolve soluble phases<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Quenching<\/strong><\/td><td>Cold water \u2013 rapid cooling to retain supersaturated solid solution<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Aging (T6\/T651)<\/strong><\/td><td>120\u2011175\u00b0C, 12\u201124 hours (depending on temper)<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Overaging (T73\/T7351)<\/strong><\/td><td>Higher aging temperatures (typically 175\u2011200\u00b0C) for SCC resistance<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udd27 Cold Working<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Conventional methods are used to readily cold\u2011work Aluminium 7475 in the annealed condition. However, as the alloy work\u2011hardens, it becomes progressively more difficult to form.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83d\udeab Welding \u2013 Important Warning<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Do not attempt to weld Aluminium 7475 by conventional fusion methods.<\/strong> The alloy is highly susceptible to hot cracking due to its zinc and copper content. Approved joining methods include:<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Riveting<\/strong> \u2013 the traditional aerospace approach<\/li>\n\n\n\n<li><strong>Bolting<\/strong> \u2013 suitable for many structural applications<\/li>\n\n\n\n<li><strong>Adhesive bonding<\/strong> \u2013 increasingly used in composite\u2011aluminium hybrid structures<\/li>\n\n\n\n<li><strong>Friction stir welding<\/strong> \u2013 a solid\u2011state process that may be applicable in certain specialised applications<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\ud83c\udfa8 Anodising<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Aluminium 7475 responds well to anodising. When properly processed, the alloy produces a <strong>uniform and shiny anodised finish<\/strong> with no surface defects. This makes it suitable for applications requiring both high strength and an attractive, corrosion\u2011resistant surface.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<div style=\"height:75px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Why Choose Aluminium 7475?<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">\u2705 Advantages<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Exceptional fracture toughness<\/strong> \u2013 approximately 40% higher than 7075, enabling damage\u2011tolerant designs<\/li>\n\n\n\n<li><strong>Very high strength<\/strong> \u2013 comparable to 7075, with ultimate tensile strength up to 586 MPa<\/li>\n\n\n\n<li><strong>Excellent fatigue crack propagation resistance<\/strong> \u2013 superior to most other high\u2011strength aluminium alloys<\/li>\n\n\n\n<li><strong>Good machinability<\/strong> \u2013 70% rating, with best results in the annealed condition<\/li>\n\n\n\n<li><strong>Heat treatable<\/strong> \u2013 properties can be tailored through thermal processing<\/li>\n\n\n\n<li><strong>Responsive to anodising<\/strong> \u2013 produces a uniform, shiny surface finish<\/li>\n\n\n\n<li><strong>Good corrosion resistance<\/strong> \u2013 comparable to 7075, with overaged tempers available for SCC resistance<\/li>\n\n\n\n<li><strong>Fully recyclable<\/strong> \u2013 sustainable for aerospace and defence applications<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\u274c Limitations<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Not weldable by conventional fusion methods<\/strong> \u2013 must be joined by riveting, bolting, or adhesive bonding<\/li>\n\n\n\n<li><strong>Higher cost than 7075<\/strong> \u2013 due to tighter composition and process control<\/li>\n\n\n\n<li><strong>Significant springback in heat\u2011treated condition<\/strong> \u2013 forming should be done in the annealed state<\/li>\n\n\n\n<li><strong>Susceptible to stress\u2011corrosion cracking<\/strong> in T6 temper \u2013 requires overaging for critical applications<\/li>\n\n\n\n<li><strong>Not suitable for high\u2011temperature service above approximately 120\u00b0C<\/strong> \u2013 strength degrades with prolonged thermal exposure<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<div style=\"height:75px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<h2 class=\"wp-block-heading\">Summary<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Aluminium 7475 (Aluminum 7475) is the <strong>second\u2011generation aerospace alloy<\/strong> that solved the toughness problem of the 7000 series. While 7075 aluminium revolutionised high\u2011strength applications, 7475 took the next step \u2013 delivering <strong>comparable strength with approximately 40% higher fracture toughness<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">From the fuselage skins and wing panels of commercial airliners to fracture\u2011critical components in military aircraft, Aluminium 7475 provides the <strong>damage tolerance<\/strong> that modern aerospace designs demand. It is not a general\u2011purpose alloy; it is a specialist \u2013 the choice for engineers who must balance high strength with the certainty that a crack will not lead to sudden, catastrophic failure.<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">If your application is <strong>fracture\u2011critical<\/strong> and weight is at a premium, Aluminium 7475 is the proven, trusted solution. For the latest technical data and real\u2011time alloy comparisons, explore the <strong><a href=\"https:\/\/aluminiummagazine.com\/webtools\/alloy-comparison-tool.html\">Aluminium Alloy Comparison Tool<\/a><\/strong>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<div style=\"height:75px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<h2 class=\"wp-block-heading\">\ud83d\udcda Related Articles<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Deepen your understanding of aluminium alloys with these curated guides:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong><a href=\"https:\/\/aluminiummagazine.com\/webtools\/alloy-comparison-tool.html\">Aluminium Alloy Comparison Tool<\/a><\/strong> \u2013 Compare 40+ aluminium alloys side by side to find the perfect material for your project<\/li>\n\n\n\n<li><strong><a href=\"https:\/\/aluminiummagazine.com\/mag\/aluminium\/aluminium-7075.html\">Aluminium 7075: The Original High\u2011Strength Aerospace Alloy<\/a><\/strong> \u2013 The first\u2011generation 7000 series alloy that set the standard<\/li>\n\n\n\n<li><strong><a href=\"https:\/\/aluminiummagazine.com\/mag\/aluminium\/aluminum-2024-alloy.html\">Aluminium 2024: The Copper Alloy for Aircraft Structures<\/a><\/strong> \u2013 Another key aerospace alloy, with different property trade\u2011offs<\/li>\n\n\n\n<li><strong><a href=\"https:\/\/aluminiummagazine.com\/mag\/faqs\/why-is-aluminum-used-for-aircraft-bodies.html\">Why Is Aluminum Used for Aircraft Bodies?<\/a><\/strong> \u2013 Understanding the role of 7000 series alloys in aerospace<\/li>\n\n\n\n<li><strong><a href=\"https:\/\/aluminiummagazine.com\/mag\/aluminium\/aluminium-6061-t6-alloy-properties-machining-applications-guide.html\">Aluminium 6061 T6: Properties, Machining &amp; Applications<\/a><\/strong> \u2013 The general\u2011purpose heat\u2011treatable alloy for non\u2011critical structures<\/li>\n<\/ul>\n<\/p><div class=\"pai-ad\" style=\"min-height:250px;visibility:hidden;\"><span style=\"display: block; text-align: center; font-size: 10px; margin: 0 0 10px 0; color: #999999;\">Ads<\/span>\r\n<!-- Display-300x250-1 -->\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:inline-block;width:300px;height:250px\"\r\n     data-ad-client=\"ca-pub-3838168351244230\"\r\n     data-ad-slot=\"9933646018\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script><\/div><script>document.addEventListener(\"DOMContentLoaded\",function(){\n        if(window.innerWidth <= 768){\n            if (\"immediate\" === \"delay\") {\n                setTimeout(function(){document.querySelectorAll(\".pai-ad\").forEach(el=>el.style.visibility=\"visible\")},0);\n            } else if (\"immediate\" === \"scroll\") {\n                window.addEventListener(\"scroll\",function(){\n                    let s=window.scrollY\/(document.body.scrollHeight-window.innerHeight);\n                    if(s>0.1){\n                        document.querySelectorAll(\".pai-ad\").forEach(el=>el.style.visibility=\"visible\");\n                    }\n                });\n            } else {\n                document.querySelectorAll(\".pai-ad\").forEach(el=>el.style.visibility=\"visible\");\n            }\n        } else {\n            document.querySelectorAll(\".pai-ad\").forEach(el=>el.remove());\n        }\n    });<\/script>","protected":false},"excerpt":{"rendered":"<p>Aluminium 7475 \u2013 also known as Aluminum 7475 \u2013 is a heat-treatable aluminium-zinc-magnesium-copper alloy that represents the second generation of the 7000 series. Developed by Alcoa and registered in 1969 as a controlled\u2011toughness alloy, 7475 aluminum offers a fracture toughness approximately 40% greater than the industry\u2011standard 7075 while maintaining comparable high strength. It is the &#8230; <a title=\"Aluminium 7475: The Second-Generation Aerospace Alloy for Superior Fracture Toughness\" class=\"read-more\" href=\"https:\/\/aluminiummagazine.com\/mag\/aluminium\/aluminium-7475-aluminum-7475-alloy-properties-aerospace-guide.html\" aria-label=\"Read more about Aluminium 7475: The Second-Generation Aerospace Alloy for Superior Fracture Toughness\">Read more<\/a><\/p>\n","protected":false},"author":12,"featured_media":17713,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[721],"tags":[4111,4109],"class_list":["post-17712","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-aluminium","tag-aluminium-alloys","tag-aluminum"],"_links":{"self":[{"href":"https:\/\/aluminiummagazine.com\/mag\/wp-json\/wp\/v2\/posts\/17712","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/aluminiummagazine.com\/mag\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/aluminiummagazine.com\/mag\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/aluminiummagazine.com\/mag\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/aluminiummagazine.com\/mag\/wp-json\/wp\/v2\/comments?post=17712"}],"version-history":[{"count":0,"href":"https:\/\/aluminiummagazine.com\/mag\/wp-json\/wp\/v2\/posts\/17712\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/aluminiummagazine.com\/mag\/wp-json\/wp\/v2\/media\/17713"}],"wp:attachment":[{"href":"https:\/\/aluminiummagazine.com\/mag\/wp-json\/wp\/v2\/media?parent=17712"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/aluminiummagazine.com\/mag\/wp-json\/wp\/v2\/categories?post=17712"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/aluminiummagazine.com\/mag\/wp-json\/wp\/v2\/tags?post=17712"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}