Can 7075-T6 be welded?

Generally NO — 7075 is considered UNWELDABLE by conventional fusion welding processes. The problem is hot-cracking (solidification cracking) in the fusion zone and liquidation cracking in the partially melted zone of the heat-affected region. The Cu content (1.2-2.0%) widens the solidification range, and the Zn+Mg combines to form low-melting-point eutectic phases at grain boundaries. Friction stir welding (FSW) can successfully join 7075 without melting — this is how SpaceX welds 7075 aluminum-lithium alloy for rocket propellant tanks. For bolted/riveted assemblies (the standard joining method for 7075), specify NAS or MS aerospace fasteners in cadmium-plated alloy steel or A286 CRES for corrosion compatibility.

How does 7075-T6 compare to 2024-T3?

7075-T6 is significantly stronger (yield: 503 MPa vs 345 MPa for 2024-T3 — +45%) but less damage-tolerant (lower fracture toughness, higher fatigue crack growth rate). 2024-T3 has superior fatigue resistance and is preferred for lower wing skins and fuselage skins where fatigue crack propagation (not static strength) governs the design. 7075-T6 is preferred for upper wing skins (compression-dominated, strength-critical) and internal structure (frames, bulkheads). 7075-T6 is also significantly more susceptible to stress-corrosion cracking in the short-transverse direction — T7351 temper is used when SCC resistance is critical, with a strength penalty of approximately 10-15%.

Aluminum 7075-T6: Aerospace-Strength Al-Zn-Mg-Cu Alloy — Aircraft Structures & Hoch-Stress Teile

ASTM B209 / AMS 4045 / AMS-QQ-A-250/12 · Published: 2026-05-31 · Updated: July 2026

Quick Reference

7075-T6 is the highest-strength conventional aluminum alloy, with a specific strength (strength-to-weight ratio) comparable to mild steel at one-third the weight. It is a heat-treatable Al-Zn-Mg-Cu precipitation-hardening alloy (7xxx series),...

7075-T6 ist der highest-strength conventional aluminum alloy, mit ein spezifisch strength (strength-zu-weight ratio) comparable zu mild steel bei one-third der weight. Es ist ein heat-treatable Al-Zn-Mg-Cu precipitation-hardening alloy (7xxx series), achieving sein properties durch solution treatment bei 465-480°C, wasser quenching, und artificial aging bei 120°C für 24 hours (T6 temper). Der primär strengthening precipitate ist MgZn₂ (eta-prime phase, metastable GP zones). 7075-T6 ist der dominant structural aluminum für aircraft ober wing skins, fuselage frames, und bulkheads ein commercial und military aircraft (Boeing 737/777/787, Airbus A320/A350, F-16, F-35). Ein der ground, es ist used für hoch-stress bicycle frames, rock-climbing ausrüstung, und M16/AR-15 rifle receivers.

Quick Facts

Kategorie	Aluminum Alloy
Norm	`ASTM B209 / AMS 4045 / AMS-QQ-A-250/12`
Density	2.81 g/cm³
Yield Strength	503 MPa (73 ksi) typical for plate ≤25 mm
Tensile Strength	572 MPa (83 ksi) typical for plate ≤25 mm

Detailed Mechanical Properties

Elongation	11% (T6)
Härte	150 HB
Streckgrenze	503 MPa
Zugfestigkeit	572 MPa

Physical Eigenschaften

Schmelzpunkt	477-635°C
Wärmeleitfähigkeit	130 W/m·K bei 20°C
Dichte	2.81 g/cm³

Global Equivalents & Cross-Referenz

Alternative Norm / Güte	Action
EN AW-7075	Compare
DIN AlZnMgCu1.5	Compare
JIS A7075P	Compare
GB 7A04	Compare
Duralumin 7075	Compare

Heat Treatment & Processing

Lösung Heat Treat	460-480°C, wasser quench
Aging	120°C, 24h (T6 temper)
Hinweis	7075-T6 ist der highest-strength aluminum alloy commonly available. Used in aircraft structures und hoch-stress components.

Welding & Fabrication

Preheat	NICHT recommended für fusion welding — 7075 ist considered unweldable durch conventional methods due zu heiß cracking susceptibility
Filler Metal	Tun nicht weld. Verwenden mechanical fastening oder friction stir welding nur.
Schweißeignung Rating	Poor — fusion welding nicht recommended. Friction stir welding ist der preferred joining method.

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Frequently Asked Questions

Können 7075-T6 sein welded?

Generally NEIN — 7075 ist considered UNWELDABLE durch conventional fusion welding processes. Der problem ist heiß-cracking (solidification cracking) in der fusion zone und liquidation cracking in der partially melted zone von der heat-affected region. Der Cu content (1.2-2.0%) widens der solidification bereich, und der Zn+Mg combines zu form niedrig-melting-point eutectic phases bei grain boundaries. Friction stir welding (FSW) können successfully join 7075 ohne melting — dies ist wie SpaceX welds 7075 aluminum-lithium alloy für rocket propellant tanks. Für bolted/riveted assemblies (der standard joining method für 7075), specify NAS oder MS aerospace fasteners in cadmium-plated alloy steel oder A286 CRES für corrosion compatibility.

Wie tut 7075-T6 compare zu 2024-T3?

7075-T6 ist significantly stronger (yield: 503 MPa vs 345 MPa für 2024-T3 — +45%) but less damage-tolerant (unter fracture toughness, higher fatigue crack growth rate). 2024-T3 hat superior fatigue widerstand und ist preferred für unter wing skins und fuselage skins wo fatigue crack propagation (nicht static strength) governs der design. 7075-T6 ist preferred für ober wing skins (compression-dominated, strength-kritisch) und internal structure (frames, bulkheads). 7075-T6 ist auch significantly mehr susceptible zu stress-corrosion cracking in der kurz-transverse direction — T7351 temper ist used wenn SCC widerstand ist kritisch, mit ein strength penalty von approximately 10-15%.

References & International Standards

ASTM International. Norm Specifications für Stahl & Metal Alloys. astm.org
International Organization für Standardization (ISO). Metallic Materials — Cross-Referenz Database. iso.org
American Iron und Stahl Institute (AISI). Stahl Güte Designations & Equivalents. steel.org
European Committee für Standardization (CEN). EN Stahl Standards & Numbering System. cencenelec.eu