Aluminum Alloys — Family Index
Tier-3 family index for the full Aluminum Association (AA) designation system: every wrought series 1xxx–8xxx, the cast 3-digit-plus-decimal system, and the complete temper code matrix (F / O / H / W / T). Aluminum is the second-most-used structural metal after steel, with a density of ~2.70 g/cm³ (one-third of steel), excellent corrosion resistance from the native Al₂O₃ passive layer, and a usable strength range from ~70 MPa (1xxx-O) to ~600+ MPa (7068-T6).
1. At a glance
Wrought system (4 digits, AA xxxx). First digit = principal alloying element. Defined in ANSI H35.1 / EN 573-1.
| Series | Principal alloying element | Heat-treatable? | Typical UTS | Hallmark use |
|---|---|---|---|---|
| 1xxx | ≥99.0% Al (commercial purity) | No | 70–185 MPa | Foil, conductors, chem equipment |
| 2xxx | Copper (Cu) | Yes (age-hardening) | 185–540 MPa | Aircraft skin, rivets |
| 3xxx | Manganese (Mn) | No | 110–285 MPa | Beverage cans, sheet metal |
| 4xxx | Silicon (Si) | Sometimes | 170–380 MPa | Weld/braze filler, pistons |
| 5xxx | Magnesium (Mg) | No | 125–385 MPa | Marine, pressure vessels |
| 6xxx | Mg + Si | Yes (Mg₂Si precipitates) | 125–400 MPa | Structural extrusions |
| 7xxx | Zinc (Zn) | Yes (MgZn₂ precipitates) | 220–620 MPa | Aerospace structure |
| 8xxx | Other (Li, Fe, Sn, …) | Varies | 290–550 MPa | Al-Li aerospace, bearing |
Cast system (3-digit + decimal, AA xxx.x). Defined in ANSI H35.1 / EN 1706.
| Series | Principal element | Examples | Notes |
|---|---|---|---|
| 1xx.x | ≥99.00% Al | 100.0 | Electrical rotors |
| 2xx.x | Cu | 201, 206, 242 | High-strength sand cast, poor castability |
| 3xx.x | Si + Cu and/or Mg | 319, 355, 356, 380 | Most common (>60% of all Al castings) |
| 4xx.x | Si | 413, 443 | Excellent fluidity, low strength |
| 5xx.x | Mg | 511, 535 | Marine castings, corrosion-resistant |
| 6xx.x | (unused) | — | Reserved |
| 7xx.x | Zn | 712, 713, 771 | Age-hardenable at room temp |
| 8xx.x | Sn | 850, 851 | Bearings, journals |
| 9xx.x | Other | — | Reserved |
Decimal suffix: .0 = casting (finished part), .1 = ingot (chemistry slightly different to allow remelt loss), .2 = secondary ingot.
Heat-treatable vs not.
- Heat-treatable (age-hardenable): 2xxx, 6xxx, 7xxx, most 8xxx (Al-Li), some 4xxx (Si+Cu+Mg), most 2xx.x / 3xx.x / 7xx.x cast.
- Non-heat-treatable (strengthened only by cold work): 1xxx, 3xxx, 5xxx, pure 4xxx.
Temper codes (suffix after -). F as-fab; O annealed; H strain-hardened (non-HT alloys); W unstable solutionized; T heat-treated. T6 = solution heat-treated + artificially aged, the workhorse temper for 6061 and 7075.
2. Designation primer
Wrought (AA xxxx)
6 0 6 1
│ │ │ │
│ │ └─┴── identifies specific alloy within the series (2nd–4th digit)
│ │ For 1xxx: last two digits = decimal %Al above 99.00 (1050 = 99.50% Al min)
│ └────── modification of original alloy (0 = original; 1, 2, … = revision)
└──────── principal alloying element series
Example: 6061 = 6xxx series (Mg+Si), original alloy (2nd digit 0), identifier 61. Registered with Aluminum Association ~1935.
Cast (AA xxx.x)
3 5 6 . 0
│ │ │ │
│ │ │ └── product form: .0 casting, .1 standard ingot, .2 special ingot
│ └─┴────── alloy identifier within the series
└────────── principal alloying element series (3xx.x = Si + Cu/Mg)
A prefix letter (A356, B356) indicates a controlled-impurity modification — typically lower Fe content (A356 has Fe ≤0.20% vs 356 at ≤0.50%), giving better ductility.
Temper codes (full)
| Code | Meaning |
|---|---|
| F | As-fabricated. No control of thermal or strain-hardening conditions. Mechanical limits not specified. |
| O | Annealed. Lowest strength, highest ductility. Subgroups: O1 high-temp anneal-and-slow-cool; O2 thermo-mechanically treated; O3 homogenized. |
| H1x | Strain-hardened only. Second digit = degree: H12 1/4-hard, H14 1/2-hard, H16 3/4-hard, H18 full-hard, H19 extra-hard. |
| H2x | Strain-hardened and partially annealed. H22, H24, H26, H28. |
| H3x | Strain-hardened and stabilized (low-temp heat to remove age-softening of Mg-rich 5xxx). H32, H34, H36, H38. |
| H4x | Strain-hardened and lacquered/painted (heat from coating cycle affects properties). |
| W | Solution heat-treated only. Unstable temper; ages naturally at room temperature. Used for time-quench-formed parts (e.g. 2024-W). |
| T1 | Cooled from elevated-temp shaping + naturally aged. Common for extrusions. |
| T2 | Cooled from elevated-temp shaping + cold-worked + naturally aged. |
| T3 | Solution heat-treated + cold-worked + naturally aged to substantially stable condition. (2024-T3 sheet.) |
| T4 | Solution heat-treated + naturally aged. (6061-T4.) |
| T5 | Cooled from elevated-temp shaping + artificially aged. (6063-T5 extrusions — no separate SHT.) |
| T6 | Solution heat-treated + artificially aged. The workhorse. (6061-T6, 7075-T6, 356-T6.) |
| T7 | Solution heat-treated + overaged/stabilized. Improves SCC and dimensional stability at expense of ~10–15% strength. |
| T8 | Solution heat-treated + cold-worked + artificially aged. (2024-T81, 2219-T87.) |
| T9 | Solution heat-treated + artificially aged + cold-worked. |
| T10 | Cooled from elevated-temp shaping + cold-worked + artificially aged. |
T-temper sub-codes (3 or 4 digits) specify stress-relief or aging-path variant:
- T_51 stress-relieved by stretching (1–3% permanent set). E.g. 2024-T351 plate.
- T_510 stress-relieved by stretching, no further straightening (extrusions).
- T_511 stress-relieved by stretching, minor straightening permitted.
- T_52 stress-relieved by thermal treatment.
- T_54 stress-relieved by combined stretching and thermal.
- T73 specific SCC-resistant overaging for 7xxx (two-step age: 107 °C then 163 °C).
- T76 intermediate between T6 and T73 — partial SCC resistance, ~5% strength loss.
- T74 intermediate between T73 and T76.
- T77 retrogression-and-re-age (RRA) for 7075 — T6 strength with T73 SCC resistance.
3. 1xxx series — commercial-purity aluminum
Composition: ≥99.0% Al; iron and silicon are the principal impurities. Non-heat-treatable. Strength comes only from cold work. Last two digits indicate purity (1050 = 99.50% Al; 1100 = 99.00% Al; 1199 = 99.99% Al “5N” superpurity).
| Alloy | Al min | Hallmark use | UTS-O / UTS-H18 |
|---|---|---|---|
| 1050 | 99.50% | Foil, anodized trim, chemical tanks | 76 / 145 MPa |
| 1060 | 99.60% | Bus bars, transformer windings | 70 / 130 MPa |
| 1100 | 99.00% (Cu 0.05–0.20%) | Cookware, fin stock, deep drawing | 90 / 165 MPa |
| 1199 | 99.99% | Capacitor foil, reflectors | 60 / 110 MPa |
| 1350 | 99.50% (EC grade) | Electrical conductors (overhead lines, ACSR core wire), 61% IACS conductivity | 85 / 185 MPa |
Excellent corrosion resistance, formability, and weldability; poor strength; high electrical and thermal conductivity (1350 is the electrical-conductor (EC) grade, formerly designated AA EC).
4. 2xxx series — Al-Cu, age-hardenable
Principal alloying element 1.9–6.8% Cu, often with Mg, Mn, Si. The original “Duralumin” patented 1909 by Alfred Wilm (Mg-bearing 2017-style composition) — the alloy that made all-metal aircraft possible. Strengthening from coherent CuAl₂ (θ′) and Cu-Mg-Al precipitates formed during aging.
| Alloy | Composition highlights | Typical temper | UTS | Use |
|---|---|---|---|---|
| 2011 | Cu 5.5, Pb-Bi free-machining | T3, T8 | 380 MPa | Screw-machine stock |
| 2014 | Cu 4.4 Mg 0.5 Si 0.8 Mn 0.8 | T6 | 485 MPa | Truck frames, aircraft structure |
| 2017 | Cu 4.0 Mg 0.6 Mn 0.7 | T4 | 425 MPa | Original Duralumin; rivets, forgings |
| 2024 | Cu 4.4 Mg 1.5 Mn 0.6 | T3, T351, T81 | 470 MPa (T3) | Aircraft skin, fuselage panels (Alclad) |
| 2090 | Cu 2.7 Li 2.2 | T83 | 550 MPa | First-gen Al-Li (now obsolete; replaced by 2098/2198) |
| 2098 | Cu Li Ag (3rd-gen Al-Li) | T82, T84 | 510 MPa | F-16 fuselage skins, Lockheed Martin |
| 2195 | Cu 4 Li 1 Ag | T8 | 545 MPa | Space Shuttle external tank (SLWT); SLS core stage |
| 2198 | Cu Li (3rd-gen) | T8 | 490 MPa | A350 fuselage lower skin, Falcon 9 cryogenic tank |
| 2219 | Cu 6.3 Mn 0.3 Zr V Ti | T87 | 475 MPa | Weldable; Saturn V tanks, Shuttle ET (original); cryo service |
| 2618 | Cu 2.3 Mg 1.6 Fe 1.1 Ni 1.0 | T6, T61 | 440 MPa | Heat-resistant pistons (Concorde skin, racing engines) — service to 150 °C |
Corrosion resistance is poor — 2024 in particular suffers intergranular and exfoliation corrosion when Cu segregates to grain boundaries. Standard mitigation is Alclad: a thin (~5% per side) sheet of 1100 or 7072 hot-roll-bonded to a 2024 core, providing sacrificial anodic protection.
Weldability is poor (hot cracking from low-melting eutectics) except for 2219, which is specifically designed for fusion welding.
5. 3xxx series — Al-Mn, non-heat-treatable
Manganese 0.3–1.5%; sometimes with Mg. Strengthened by solid solution + cold work. The first practical strengthening over commercially-pure 1xxx.
| Alloy | Composition | Typical temper | UTS | Use |
|---|---|---|---|---|
| 3003 | Mn 1.2 Cu 0.12 | H14 | 150 MPa | General sheet, ducts, cookware, heat exchangers |
| 3004 | Mn 1.2 Mg 1.0 | H19 | 285 MPa | Beverage-can body (~80% of all beer/soda cans worldwide) |
| 3005 | Mn 1.2 Mg 0.4 | H14 | 200 MPa | Roofing, siding, signs |
| 3104 | Mn 1.1 Mg 1.0 (controlled Fe-Si) | H19 | 295 MPa | Beverage-can body (replaces 3004 in some plants) |
| 3105 | Mn 0.55 Mg 0.5 | H14, H16 | 170 MPa | Residential siding, gutters |
3004-H19 / 3104-H19 in 0.27 mm gauge is one of the highest-volume metallic products on Earth — global beverage-can production is ~500 billion units/year.
6. 4xxx series — Al-Si, filler and pistons
Silicon 3.6–13.5% reduces melting range and improves fluidity. Most 4xxx are filler materials, not structural.
| Alloy | Si | Use |
|---|---|---|
| 4032 | 12.2 (+ Cu 0.9, Mg 1.0, Ni 0.9) | Forged pistons — low CTE, wear-resistant |
| 4043 | 5.2 | TIG/MIG filler rod for 6xxx, most 5xxx, castings |
| 4045 | 10.0 | Brazing-sheet cladding for 3003/3xxx cores |
| 4047 | 12.0 (eutectic) | Brazing filler, vacuum brazing; lowest melting range |
| 4145 | 10.0 (+ Cu 4.0) | Welding filler for 2xxx (Cu-bearing) parents |
Brazing temperatures 580–615 °C — just below the 660 °C melting point of pure Al — so process control is tight.
7. 5xxx series — Al-Mg, marine and structural
Magnesium 0.5–5.5% as principal alloying element. Strengthened by solid solution + cold work. Excellent corrosion resistance, especially in chloride (seawater) environments. Readily weldable. The default choice for marine hulls, pressure vessels, and structural sheet that must resist seawater.
| Alloy | Mg | Typical temper | UTS | Use |
|---|---|---|---|---|
| 5005 | 0.8 | H14, H34 | 140 MPa | Architectural, anodized trim |
| 5050 | 1.4 | H34 | 195 MPa | Refrigerator tubing, gasoline lines |
| 5052 | 2.5 (+ Cr) | H32, H34 | 230 MPa | General-purpose sheet, tanks, marine hardware |
| 5083 | 4.4 (+ Mn 0.7, Cr) | O, H116, H321 | 305 MPa | Marine structural — ship hulls, LNG tanks (cryogenic to −165 °C) |
| 5086 | 4.0 (+ Mn 0.4, Cr) | H116, H32 | 290 MPa | Boat hulls, armor plate |
| 5154 | 3.5 (+ Cr) | H34 | 290 MPa | Welded structures, pressure vessels |
| 5182 | 4.5 (+ Mn 0.35) | H19, H48 | 395 MPa | Beverage-can ends (lids/tabs) — higher Mg for strength |
| 5252 | 2.5 | H25, H28 | 235 MPa | Decorative trim (bright anodizing) |
| 5454 | 2.7 (+ Mn 0.8, Cr) | H32, H34 | 270 MPa | Hot-service vessels (up to 65 °C), tankers |
| 5456 | 5.1 (+ Mn 0.8, Cr) | H116, H321 | 350 MPa | High-Mg marine; armor; ballistic plate |
| 5754 | 3.1 | O, H22, H24 | 220 MPa | Automotive body-in-white panels (BIW), floor pans |
Sensitization caveat: 5xxx alloys with >3% Mg held above ~65 °C can precipitate Mg₂Al₃ (β-phase) at grain boundaries, leading to intergranular corrosion and SCC. Hence 5454 (2.7% Mg) is used for elevated-service tanks instead of 5083. The H116 and H321 tempers are specifically engineered for SCC resistance via controlled grain-boundary β-phase distribution.
8. 6xxx series — Al-Mg-Si, the extrusion workhorse
Mg + Si in approximately 2:1 ratio (forming Mg₂Si precipitates during aging). Moderate strength, excellent extrudability, good corrosion resistance, weldable, machinable. The default choice for structural shapes, architectural frames, automotive components, and almost any general-purpose application.
| Alloy | Mg / Si | Typical temper | UTS | Use |
|---|---|---|---|---|
| 6005 / 6005A | 0.5 / 0.7 | T5, T6 | 270 MPa | Extrusions; structural — rail cars, scaffolding |
| 6020 | 0.7 / 0.8 (+ Bi-Sn free-machining) | T8 | 290 MPa | Lead-free screw-machine stock |
| 6053 | 1.2 / 0.7 | T6 | 255 MPa | Wire, rivets |
| 6060 | 0.5 / 0.4 | T5, T6 | 215 MPa | Architectural extrusions (EU equivalent of 6063) |
| 6061 | 1.0 / 0.6 (+ Cu 0.28, Cr) | T4, T6, T651 | 310 MPa T6 | The workhorse. Bikes, boats, structural plate, machined parts |
| 6063 | 0.7 / 0.4 | T5, T52, T6 | 240 MPa T6 | Architectural extrusions — window frames, curtain wall, railings |
| 6066 | 1.1 / 1.4 (+ Cu, Mn) | T6 | 395 MPa | High-strength extrusion; forgings |
| 6070 | 0.8 / 1.4 (+ Cu, Mn) | T6 | 380 MPa | Heavy-duty welded structures |
| 6082 | 0.9 / 1.0 (+ Mn 0.7) | T6, T651 | 340 MPa | Structural — preferred over 6061 in Europe (higher Mn = better grain control) |
| 6101 | 0.6 / 0.5 | T6, T64 | 220 MPa | Bus-bar EC grade — 57% IACS conductivity |
| 6262 | 1.0 / 0.6 (+ Pb-Bi free-machining) | T6, T651, T9 | 400 MPa | Lead-bearing screw-machine stock (REACH-restricted, being phased out) |
| 6463 | 0.7 / 0.4 | T5, T6 | 240 MPa | Bright-trim extrusions (low Fe for anodizing clarity) |
6061-T6 and 6063-T5 dominate the world’s extruded-aluminum production. 6063 is optimized for thin-wall complex profiles at the expense of strength; 6061 for higher-strength plate and machined billet.
9. 7xxx series — Al-Zn(-Mg-Cu), highest strength
Zinc 4.5–8.7% with Mg 1.5–3.5% and often Cu 1–2.5%. Strengthening from MgZn₂ (η′ and η) precipitates. The strongest commercial aluminum alloys, used wherever specific strength is paramount.
| Alloy | Zn / Mg / Cu | Typical temper | UTS | Use |
|---|---|---|---|---|
| 7005 | 4.5 / 1.4 / — (+ Zr) | T6 | 350 MPa | Weldable structural — bicycle frames, MTB |
| 7039 | 4.0 / 2.8 / — | T6, T64 | 450 MPa | Armor plate (military vehicles) |
| 7049 | 7.6 / 2.4 / 1.5 | T73 | 540 MPa | SCC-resistant aerospace forgings |
| 7050 | 6.2 / 2.3 / 2.3 (+ Zr) | T7451, T7651 | 525 MPa | Aerospace forgings/thick plate — 777 wing ribs, 787 frames |
| 7068 | 8.0 / 2.7 / 2.1 | T6511 | 700 MPa | Highest-strength commercial Al; precision rifle bolts, recoilless tools |
| 7075 | 5.6 / 2.5 / 1.6 (+ Cr) | T6, T651, T73, T7351 | 570 MPa T6 | The aerospace workhorse. Wing spars, fuselage frames, fittings |
| 7079 | 4.3 / 3.3 / 0.6 | T6 | 540 MPa | Older aerospace forgings (largely replaced by 7050) |
| 7085 | 7.5 / 1.6 / 1.6 (+ Zr) | T7452 | 510 MPa | A380 wing ribs, F-35 bulkheads — low-quench-sensitivity for thick sections |
| 7150 | 6.4 / 2.4 / 2.2 (+ Zr) | T7751, T6151 | 600 MPa | Aerospace plate (777-class) |
| 7178 | 6.8 / 2.8 / 2.0 (+ Cr) | T6 | 605 MPa | Upper wing skin of older transport aircraft |
| 7475 | 5.7 / 2.3 / 1.5 (+ Cr) | T651, T7351 | 560 MPa | Damage-tolerant, fracture-tough (controlled Fe/Si) — wing-skin alternative to 7075 |
SCC caveat: 7xxx is highly sensitive to stress-corrosion cracking, especially in T6 temper in moist/chloride environments. The T73 temper (overaged: two-step age, second at 163 °C) sacrifices ~15% UTS for substantial SCC resistance. T76 splits the difference. T77 (retrogression-and-re-age, Cytec/Alcoa proprietary) recovers T6-level strength with T73 SCC resistance via a short high-T retrogression followed by re-aging.
10. 8xxx series — miscellaneous (Li, Fe, Sn)
Reserved for alloys whose principal element doesn’t fit 2–7xxx. In practice dominated by Al-Li, with iron-bearing foil grades and tin-bearing bearing alloys.
| Alloy | Composition | Typical use |
|---|---|---|
| 8006 | Fe 1.5 Mn 0.5 | Heat exchanger fin stock |
| 8009 | Fe 8.5 V 1.3 Si 1.8 (rapidly solidified) | Elevated-temp aerospace (Lockheed P&W research, limited production) |
| 8011 | Fe 0.8 Si 0.7 | Household foil, capacitor foil |
| 8024 | Al-Li 2nd-gen development | Cryogenic tank development |
| 8090 | Li 2.4 Cu 1.2 Mg 0.7 Zr | First-gen Al-Li (Eurofighter Typhoon, A330 floor beams) |
| 8093 / 8091 | Li-bearing | Westland EH-101 helicopter |
Al-Li alloys offer ~10% density reduction (each 1% Li drops density 3%) plus 5% modulus increase per 1% Li, attractive for aerospace specific stiffness. Drawbacks: poor short-transverse properties, complex stretch-forming, and high alloy cost (Li ~$70/kg). 2nd- and 3rd-generation Al-Li alloys (2098, 2195, 2198, 2050, 2055) have migrated back into the 2xxx series since copper rather than lithium is now the principal element.
11. Cast aluminum alloys
Cast aluminum accounts for ~25% of all aluminum tonnage. The 3xx.x (Al-Si-Cu and Al-Si-Mg) family dominates.
| Alloy | Composition highlights | Process | Typical temper | UTS | Use |
|---|---|---|---|---|---|
| 201.0 | Cu 4.6 Ag Mg | Sand, perm-mold | T6, T7 | 415 MPa | Highest-strength Al casting; aerospace, missile bodies |
| 206.0 | Cu 4.6 Mg | Sand, perm-mold | T6, T7 | 415 MPa | Premium structural castings |
| 295.0 | Cu 4.5 Si 1.0 | Sand | T6 | 250 MPa | General-purpose |
| 319.0 | Si 6.0 Cu 3.5 | Sand, perm-mold | F, T5, T6 | 235 MPa | General — engine blocks, manifolds, transmission cases |
| 332.0 | Si 9.5 Cu 3.0 Mg 1.0 | Perm-mold | T5 | 245 MPa | Pistons (gasoline engines) |
| 333.0 | Si 9.0 Cu 3.5 Mg 0.3 | Perm-mold | T5, T6 | 290 MPa | Engine parts |
| 355.0 | Si 5.0 Cu 1.25 Mg 0.5 | Sand, perm-mold | T6, T71 | 240 MPa | Aircraft fittings, pump bodies |
| 356.0 | Si 7.0 Mg 0.32 | Sand, perm-mold | T6 | 230 MPa | The cast workhorse — wheels, transmission housings, structural |
| A356.0 | Si 7.0 Mg 0.35 (Fe ≤0.20) | Sand, perm-mold | T6, T61 | 280 MPa | Premium 356 — alloy wheels (cast + spun), aerospace |
| A357.0 | Si 7.0 Mg 0.55 Be | Premium investment | T6 | 320 MPa | Aerospace structural castings |
| 380.0 / A380 | Si 8.5 Cu 3.5 (low Mg) | High-pressure die | F | 320 MPa | Die-casting workhorse — appliances, electronics housings, brackets |
| 383.0 | Si 10.5 Cu 2.5 | Die | F | 310 MPa | Improved die-casting fluidity over 380 |
| 390.0 | Si 17 Cu 4.5 Mg 0.6 | Die, sand | T5, T6 | 280 MPa | Hypereutectic — engine blocks (Vega, GM Northstar) — wear resistance |
| 413.0 | Si 12 (eutectic) | Die | F | 295 MPa | Thin-wall die castings, intricate shapes |
| 443.0 | Si 5.2 | Sand, perm-mold | F | 130 MPa | Marine castings, fittings |
| 535.0 (Almag 35) | Mg 7.0 | Sand | F (no HT needed) | 240 MPa | Marine, corrosion-resistant; ages naturally |
| 713.0 (Tenzaloy) | Zn 7.5 Cu 0.7 Mg 0.35 | Sand, perm-mold | F, T5 | 240 MPa | Natural-aging castings — no solution treatment |
| 771.0 | Zn 7.0 Mg 0.9 Cr 0.13 | Sand | T5, T51, T6, T71 | 330 MPa | High-strength sand castings |
| 850.0 | Sn 6.2 Cu 1.0 Ni 1.0 | Sand, perm-mold | T5 | 140 MPa | Plain bearings, bushings |
Si modification: hypoeutectic 3xx.x alloys (Si 5–11%) form coarse acicular eutectic Si platelets that act as crack initiators. Adding ~0.01–0.04% strontium (Sr) — or historically Na — modifies the Si morphology to fine fibrous form, raising elongation 2–3×. Sr is the modern standard (longer fade time than Na).
Grain refinement: Al-5Ti-1B or Al-3Ti-1B master alloys added at 0.5–2 kg/tonne refine α-Al grain size from millimeters to <200 µm via TiB₂ nucleant particles.
12. Temper details — quick reference
| Temper | Process sequence | Strength relative to T6 | Use |
|---|---|---|---|
| O | Full anneal (typically 415 °C / 2 h, slow cool) | ~25% | Forming, deep drawing |
| T3 | SHT → cold-work → natural-age | ~95% (2024) | 2024 sheet (aircraft skin) |
| T351 | T3 + stretch-relieved 1.5–3% | ~95% | 2024 plate (stress-relieved) |
| T4 | SHT → natural-age | ~80% | 6061 prior to forming |
| T451 | T4 + stretch-relieved | ~80% | 2024-T451 plate |
| T5 | Cool from hot-shape → artificial age | ~85% (6063) | 6063 extrusions (no separate SHT) |
| T6 | SHT → artificial-age (typically 175 °C / 8 h for 6061; 120 °C / 24 h for 7075) | 100% | 6061, 7075, 356 — the standard high-strength temper |
| T651 | T6 + stretch-relieved 1.5–3% | 100% | Thick plate (low residual stress) |
| T7 | SHT → overaged | ~85% | Generic overaged |
| T73 | SHT → two-step overage (107 °C / 8 h + 163 °C / 24 h) | ~85% (7075) | 7075 SCC-resistant forgings |
| T7351 | T73 + stretch | ~85% | 7075 thick plate, SCC service |
| T76 | SHT → intermediate overage | ~92% | Compromise SCC + strength |
| T8 | SHT → cold-work → artificial-age | ~110% (2219-T87) | 2024-T81 sheet, 2219-T87 pressure vessels |
| T87 | T8 with 7% cold-work | ~115% | 2219 cryo tanks |
| T9 | SHT → artificial-age → cold-work | ~110% | Drawn tube |
| T10 | Cool from hot-shape → cold-work → artificial-age | ~85% | Less common |
13. Cross-system equivalents
| AA (US) | EN AW (Europe) | ISO | JIS (Japan) | UNS |
|---|---|---|---|---|
| 1050 | EN AW-1050A | Al 99.5 | A1050 | A91050 |
| 1100 | EN AW-1100 | Al 99.0 Cu | A1100 | A91100 |
| 2014 | EN AW-2014 | AlCu4SiMg | A2014 | A92014 |
| 2017 | EN AW-2017A | AlCu4MgSi | A2017 | A92017 |
| 2024 | EN AW-2024 | AlCu4Mg1 | A2024 | A92024 |
| 2219 | EN AW-2219 | AlCu6Mn | A2219 | A92219 |
| 3003 | EN AW-3003 | AlMn1Cu | A3003 | A93003 |
| 3004 | EN AW-3004 | AlMn1Mg1 | A3004 | A93004 |
| 4043 | EN AW-4043A | AlSi5 | A4043 | A94043 |
| 5052 | EN AW-5052 | AlMg2.5 | A5052 | A95052 |
| 5083 | EN AW-5083 | AlMg4.5Mn0.7 | A5083 | A95083 |
| 5086 | EN AW-5086 | AlMg4 | A5086 | A95086 |
| 5754 | EN AW-5754 | AlMg3 | A5754 | A95754 |
| 6061 | EN AW-6061 | AlMg1SiCu | A6061 | A96061 |
| 6063 | EN AW-6063 | AlMg0.7Si | A6063 | A96063 |
| 6082 | EN AW-6082 | AlSi1MgMn | A6082 | A96082 |
| 7050 | EN AW-7050 | AlZn6CuMgZr | A7050 | A97050 |
| 7075 | EN AW-7075 | AlZn5.5MgCu | A7075 | A97075 |
| 8011 | EN AW-8011A | AlFeSi | A8011 | A98011 |
| 356.0 | EN AC-42100 (AlSi7Mg0.3) | AlSi7Mg | AC4C | A03560 |
| 380.0 | EN AC-46500 (AlSi8Cu3) | AlSi8Cu3 | ADC10 | A03800 |
| 390.0 | EN AC-48000 (AlSi17Cu4Mg) | AlSi17Cu4Mg | — | A03900 |
14. Selection heuristics
| Requirement | First-pick alloy(s) | Notes |
|---|---|---|
| Deep-drawn sheet, hand-formed | 1100-O, 3003-O | Maximum ductility |
| General-purpose forming sheet | 3003-H14, 5052-H32 | Good strength + formability |
| Beverage-can body | 3004-H19 / 3104-H19 | 0.27 mm gauge, drawn-and-ironed |
| Beverage-can end | 5182-H19 | Higher Mg for tab strength |
| Aircraft fuselage skin | 2024-T3 (Alclad) | High fatigue, damage-tolerant |
| Aircraft upper wing skin | 7075-T6, 7150-T7751, 7178-T6 | Highest compressive strength |
| Aircraft lower wing skin | 2024-T351, 2324-T39, 2198-T8 | Tension-fatigue critical |
| Aerospace forgings/thick plate | 7050-T7451, 7085-T7452 | Low quench-sensitivity for thick sections |
| SCC-prone aerospace | 7075-T73, 7050-T74 | Overaged for SCC resistance |
| Marine hull | 5083-H116, 5086-H116 | SCC-resistant marine tempers |
| Cryogenic pressure vessel | 5083-O, 2219-T87 | Toughness at LNG / LH₂ temps |
| Architectural extrusion (windows, curtain wall) | 6063-T5, 6060-T6 | Excellent surface finish, anodizing |
| Structural extrusion (beams, tubing) | 6061-T6, 6082-T6 | Higher strength |
| General machined part | 6061-T651 | Best machinability + availability |
| Free-machining screw stock | 2011-T3, 6262-T9, 6020-T8 | Pb/Bi additions; 6020 is Pb-free |
| Sand-cast wheel / housing | A356-T6, 356-T6 | Premium ductility |
| High-pressure die-cast housing | A380, 383 | Dominant die-cast alloy |
| Engine block (Si-rich, low CTE) | 319, 390 | 390 hypereutectic — bore wear |
| Welded structural | 5083 (marine), 6082 (general), 5454 (hot service) | Avoid 2xxx, 7xxx fusion welds |
| Conductors | 1350 (cable), 6101 (bus bar) | 61% / 57% IACS |
| Foil | 1100, 1199, 8011 | <0.2 mm gauge |
| Pistons | 4032, 332, 2618 (high-T) | Si or Cu+Ni heat resistance |
| Bearings | 850.0 | Sn-bearing tribology |
15. Joining
| Process | Best parents | Filler | Notes |
|---|---|---|---|
| GTAW (TIG) | 1xxx, 3xxx, 5xxx, 6xxx | 4043 (general), 5356 (5xxx-to-5xxx, Mg ≥3%), 4047 (low-melt) | AC current, He/Ar shield. Clean oxide before welding. |
| GMAW (MIG) | Same as TIG | Same; spool-gun for soft wire | Spray transfer; high deposition |
| Friction-stir welding (FSW) | 2xxx, 7xxx (otherwise unweldable), 6xxx | None (solid-state) | Aerospace standard for 2024/7075 panels; SpaceX Falcon tanks |
| Resistance spot weld | 5xxx, 6xxx body sheet | None | Automotive; aluminum requires higher current than steel |
| Brazing (CAB, vacuum, dip) | 3003, 6951 core with 4045/4047 clad | Pre-clad brazing sheet | Heat exchangers, radiators; 580–615 °C |
| Soldering | 1100, 3003 | Zn-Al solders, low-T (300 °C) | Limited; corrosion concerns |
| Mechanical (rivets, bolts, self-piercing) | All | 2017 or 5056 rivets | Self-piercing rivets (SPR) dominate Al BIW |
| Adhesive bonding | All | Epoxy, polyurethane | Aerospace primary structure (e.g. Boeing 787 stringers); pretreatment (chromate, sol-gel, PAA) critical |
Weldability rules of thumb:
- 1xxx, 3xxx, 5xxx, 6xxx — readily fusion-weldable.
- 2xxx (except 2219), 7xxx (except 7005/7039) — not fusion-weldable; hot cracking from Cu-Mg or Zn eutectics. Use FSW, mechanical, or adhesive.
- HAZ softening of 6061/6063 welds drops strength ~50% in the heat-affected zone — design must account for it (use thicker sections at joints, or post-weld T6 re-age where possible).
16. Cross-references
- materials-aluminum — Tier-2 introduction to aluminum metallurgy, processing, and surface treatment.
- casting-forging-forming — bulk forming processes feeding cast alloy selection.
- joining-welding — generalized joining processes; this note covers Al-specific details.
- casting-processes — sand vs permanent-mold vs die-cast process detail (informs 3xx.x/380 selection).
- welding-processes — process-specific arc/beam/solid-state weld physics.
- steel-grades — sister family-index for the other major structural metal.
- titanium-alloys — competing aerospace alloy family.
- surface-treatments — solutionizing, aging, quenching theory underlying T-tempers.
- surface-treatments — Alclad, anodizing, SCC, galvanic compatibility.
- fatigue-analysis — damage tolerance for 2024 and 7075 in aerospace.
17. Citations
- The Aluminum Association. Aluminum Standards and Data 2021 (Wrought) and Aluminum Standards and Data — Cast 2018. The authoritative US registration of every wrought (xxxx) and cast (xxx.x) chemical composition, plus typical mechanical properties. https://www.aluminum.org/
- The Aluminum Association. International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys (Teal Sheets), current edition. The “Teal Sheets” — the authoritative cross-reference list for registered alloy numbers.
- ASM International. ASM Handbook, Vol. 2: Properties and Selection — Nonferrous Alloys and Special-Purpose Materials. ASM, 1990 (10th ed.), reprinted with updates. ISBN 978-0-87170-378-1. The single most-cited handbook reference for aluminum alloys.
- Davis, J.R. (ed.). Aluminum and Aluminum Alloys (ASM Specialty Handbook). ASM International, 1993. ISBN 978-0-87170-496-2. The standalone aluminum compendium spun off from ASM Vol. 2.
- Polmear, I.J., StJohn, D., Nie, J-F., Qian, M. Light Alloys: Metallurgy of the Light Metals, 5th ed. Butterworth-Heinemann, 2017. ISBN 978-0-08-099431-4. The deepest physical-metallurgy treatment of precipitation hardening in 2xxx/6xxx/7xxx and Al-Li.
- Hatch, J.E. (ed.). Aluminum: Properties and Physical Metallurgy. ASM, 1984. ISBN 978-0-87170-176-3. Classic precipitation-hardening reference.
- EN 573-1, -2, -3, -4: Aluminium and aluminium alloys — Chemical composition and form of wrought products. Parts 1–4 cover numerical designation system, chemical-symbol system, and form-by-form chemical limits. CEN, current editions.
- EN 515: Aluminium and aluminium alloys — Wrought products — Temper designations. CEN. The European equivalent of the AA temper system; compatible nomenclature.
- EN 1706: Aluminium and aluminium alloys — Castings — Chemical composition and mechanical properties. CEN. European cast-alloy designations (AC-xxxxx).
- ANSI H35.1/H35.1(M): Alloy and Temper Designation Systems for Aluminum. The Aluminum Association / ANSI. Defines the US designation system in standards form.
- ASTM B209 (sheet/plate), B221 (extrusions), B247 (forgings), B26 (sand castings), B85 (die castings) — material specifications referenced by US-side procurement.
- AMS 4027 (6061), AMS 4045 (7075), AMS 4117 (2024), AMS-QQ-A-250 series — SAE aerospace material specifications for aircraft-grade aluminum.
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