When structural weight is critical and failure is not an option, engineers reach for two aluminum alloys above all others: 2024 and 7075. Both deliver strength levels that far exceed the general-purpose alloys used in construction or packaging. Both are heat-treatable, precision-machinable, and decades-proven in demanding aerospace and defense applications.
But they are not interchangeable. 7075 is stronger by static measurement. 2024 resists fatigue crack growth better. The difference between these two characteristics determines which alloy goes where on an aircraft — and why experienced aerospace engineers specify them for different structural zones even on the same airframe.
This guide covers every dimension of the 2024 vs 7075 aluminum comparison: mechanical properties, temper designations, fatigue and fracture behavior, corrosion resistance, applications, machinability, price, and aerospace certification requirements. By the end, you will have a clear framework for selecting the right alloy for your specific application.
Both alloys belong to the heat-treatable family of aluminum alloys — meaning their strength comes primarily from a controlled heat treatment process rather than cold working. This allows them to achieve strength levels that are simply not reachable by work-hardened alloys like 1100, 3003, or 5052.
2024 belongs to the 2xxx series, where copper is the primary alloying element. Copper forms strengthening precipitates (Al2CuMg) during aging that dramatically increase dislocation resistance. The result is an alloy with outstanding fatigue crack growth resistance and fracture toughness — the properties that matter most in tension-loaded, cyclically stressed airframe structures.
7075 belongs to the 7xxx series, where zinc is the primary alloying element. The zinc-magnesium-copper combination produces even finer, denser strengthening precipitates (MgZn2) than 2024, pushing static tensile strength to levels approaching some steels. 7075-T6 reaches 572 MPa tensile strength — among the highest of any commercially available aluminum alloy.
The two alloys have coexisted in aerospace design for decades precisely because they serve different structural functions. Understanding those functions is the key to correct alloy selection.
The table below compares 2024 and 7075 aluminum in their most common aerospace tempers: 2024-T3 and 7075-T6. Additional tempers are covered in Section 3.
Property | 2024-T3 / T351 | 7075-T6 / T651 |
Tensile strength | 483 MPa (70 ksi) | 572 MPa (83 ksi) |
Yield strength | 345 MPa (50 ksi) | 503 MPa (73 ksi) |
Fatigue strength (R.R. Moore) | 138 MPa (20 ksi) | 159 MPa (23 ksi) |
Fracture toughness (KIc) | ~36 MPa·m½ — superior | ~27 MPa·m½ |
Crack growth rate (da/dN) | Slower — better damage tolerance | Faster |
Elongation at break | ~18% — more ductile | ~11% |
Brinell hardness | ~120 HB | ~150 HB |
Density | 2.78 g/cm³ | 2.81 g/cm³ |
Thermal conductivity | 121 W/m·K | 130 W/m·K |
Machinability | Excellent | Excellent (slightly faster) |
Weldability (fusion) | Not recommended — hot cracking risk | Not recommended — hot cracking risk |
Friction stir welding (FSW) | Acceptable | Acceptable |
Corrosion resistance | Poor — requires Alclad or anodize | Poor in T6 — T73 improves SCC |
SCC resistance (T6/T3) | Moderate | Low in T6; good in T73/T7351 |
Primary strengthening | Al-Cu-Mg (2xxx series) | Al-Zn-Mg-Cu (7xxx series) |
Relative cost | High | Higher |
Several numbers in this table deserve explanation. First, fracture toughness: 2024-T351 delivers approximately 36 MPa·m½ compared to about 27 MPa·m½ for 7075-T6 — a 33% advantage. Fracture toughness measures how much stress a material can withstand in the presence of a crack before that crack propagates catastrophically. In tension-loaded skin panels that experience tens of thousands of pressurization cycles over an aircraft's life, this matters enormously.
Second, crack growth rate: even though 7075-T6 has a slightly higher fatigue strength on a smooth-specimen basis, 2024-T3 propagates fatigue cracks more slowly under the same stress intensity conditions. This is why damage-tolerant aircraft design — the philosophy that assumes cracks will form and asks how long until they become dangerous — favors 2024 for primary tension structure.
Third, elongation: 2024-T3's 18% elongation versus 7075-T6's 11% reflects meaningfully better ductility, which contributes to its damage tolerance and also makes it easier to form in the T4 temper before aging.
The temper code is as important as the alloy number. The same base alloy in different tempers can have dramatically different strength, toughness, and corrosion resistance. Specifying the wrong temper is a common and costly procurement error.
• 2024-T3: Solution heat-treated, cold-worked, and naturally aged. The most widely specified temper for 2024 sheet and thin plate. Combines high fatigue resistance with good ductility and the damage tolerance properties that make 2024 the historical standard for fuselage and lower wing skin applications.
• 2024-T351: Solution heat-treated, stress-relieved by stretching, and naturally aged. The T351 designation indicates that the plate has been stretched to eliminate residual stresses from quenching. This produces superior dimensional stability during machining — critical for thick-plate structural components where tight tolerances are required. This temper is the standard for machined fuselage frames and bulkheads.
• 2024-T4: Solution heat-treated and naturally aged without cold working. Lower strength than T3 but better formability. Used when the part must be bent, drawn, or formed before final assembly. The natural aging can continue slowly at room temperature over time.
• 2024-T81 / T861: Artificially aged after cold work. Higher strength than T3 but reduced fracture toughness and ductility. Used in specific structural applications where maximum strength is required and the toughness trade-off is acceptable.
• 7075-T6: Solution heat-treated and artificially aged to peak strength. The strongest common temper, reaching 572 MPa tensile strength. The standard specification for compression-loaded structures, highly stressed machined parts, and applications where maximum static strength is the governing criterion. This is the temper behind the high search volumes for 7075-T6 pricing.
• 7075-T651: T6 with added stress relief by stretching. Eliminates quench-induced residual stresses, producing a plate with excellent flatness and dimensional stability for precision machining. The standard specification for machined structural plates, tooling plates, and components requiring tight tolerances after machining.
• 7075-T73: Over-aged beyond peak strength. Tensile strength drops to approximately 503 MPa — about 12% below T6 — but resistance to stress-corrosion cracking (SCC) improves dramatically. The correct temper for 7075 components in humid or marine environments, or wherever SCC risk must be minimized. Landing gear and structural fittings exposed to outdoor environments commonly specify T73.
• 7075-T7351: T73 properties with stress relief by stretching. The standard for thick machined plates in applications requiring both SCC resistance and dimensional stability. Widely used in commercial aircraft structural fittings.
• 7075-T76 / T7651: An intermediate temper between T6 and T73. Provides better corrosion resistance than T6 with less strength sacrifice than T73. Used where an optimized balance between strength and environmental durability is required.
A critical procurement note: when ordering 7075 for outdoor or humid environments, always specify T73 or T7351 rather than T6. The strength difference is modest but the SCC risk reduction is substantial. Many corrosion failures in 7075 components can be traced to T6 being used in environments that required T73.
This is the most technically important distinction between the two alloys — and the one most often misrepresented by simple property comparisons that focus only on tensile strength.
On a smooth-specimen basis, 7075-T6 has a slightly higher fatigue strength than 2024-T3: approximately 159 MPa versus 138 MPa at 10^8 cycles in a rotating-bending (R.R. Moore) test. This leads some to conclude that 7075 is better for fatigue applications. That conclusion is incorrect for structural aerospace design.
Real aircraft structures are not smooth specimens. They contain fastener holes, cutouts, stress concentrations, and surface scratches from manufacturing and handling. In the presence of these stress risers, what matters is not the fatigue initiation threshold but the rate at which fatigue cracks grow once they have initiated — and how large a crack can become before it causes catastrophic failure.
2024 aluminum is significantly tougher than 7075 in the fracture mechanics sense. Its fracture toughness (KIc) of approximately 36 MPa·m½ means it can tolerate a larger critical crack size before fast fracture, and it propagates fatigue cracks more slowly at the same stress intensity factor. Both properties are central to the damage-tolerant design philosophy required by FAA regulations for civil transport aircraft (FAR 25.571).
The practical consequence is longer inspection intervals. If a fuselage skin panel develops a fatigue crack, a 2024-T3 panel gives structural engineers more time between when the crack initiates and when it reaches critical size — measured in flight cycles, this difference can be significant. Longer inspection intervals mean lower maintenance costs over the aircraft's service life.
This is why traditional wide-body commercial aircraft design uses 2024-T3 for fuselage lower skin and lower wing skin — the tension-loaded surfaces that experience cyclic pressurization and bending loads in flight — while specifying 7075-T6 or T651 for upper wing skin and primary spars, where compressive loads dominate and static strength is the governing criterion. Both alloys work together, each performing the function it does best. Modern aluminum-lithium alloys (2xxx-Li and 7xxx-Li) are extending this design logic with weight reductions, but the underlying principle — fatigue-critical zones want 2024-family properties, strength-critical zones want 7075-family properties — remains valid.
Component / application | Best alloy | Key reason |
Fuselage lower skin (tension) | 2024-T3 | Fatigue crack growth resistance, damage tolerance |
Lower wing skin (tension) | 2024-T3 / T351 | Cyclic tension loading, fracture toughness |
Fuselage frames & bulkheads | 2024-T351 | Thick-plate machining, dimensional stability |
Upper wing skin (compression) | 7075-T6 / T651 | Compressive strength governs — no fatigue penalty |
Wing spars (flanges & webs) | 7075-T6 / T651 | Highest bending moment, strength-critical |
Landing gear components | 7075-T73 / T7351 | High static load + SCC resistance required |
Precision machined structural parts | 7075-T651 | Best strength-to-weight, excellent machinability |
UAV / drone frames | 7075-T6 | Highest strength-to-weight ratio, lightweight |
Helicopter rotor fittings | 2024-T351 | High-cycle fatigue, damage tolerance design |
Propeller blades | 2024-T3 | Rotating fatigue loading |
Pressure bulkheads | 2024-T351 | Fracture toughness, thin-gauge sheet |
High-end cycling frames / sports | 7075-T6 | Max strength-to-weight for non-fatigue-critical |
Unmanned aerial vehicles represent one of the fastest-growing markets for 7075-T6 aluminum. UAV frames must minimize weight to maximize payload and flight time, and the strength-to-weight ratio of 7075-T6 is unmatched among common aluminum alloys. Because UAV airframes typically operate in short-duration flights with lower cycle counts than manned commercial aircraft, the fatigue crack growth advantage of 2024 is less critical — making 7075-T6 the dominant choice for UAV structural components including frames, arms, and motor mounts.
7075-T6 has found a significant market in high-performance sporting goods: bicycle frames and components, climbing equipment, skateboard trucks, and precision sports equipment. These applications share the same logic as UAV frames — maximum strength at minimum weight, with cycle counts and stress histories that do not make 2024's damage tolerance advantage the determining factor.
Compared to the 5xxx and 6xxx series alloys, both 2024 and 7075 have relatively poor inherent corrosion resistance. This is a direct consequence of their high copper or zinc-copper content — the same elements that produce their exceptional strength create micro-galvanic cells at grain boundaries that accelerate pitting and stress-corrosion cracking in corrosive environments.
The standard solution for 2024 sheet in aerospace applications is Alclad: a thin layer of commercially pure aluminum (1xxx series) is metallurgically bonded to each surface of the 2024 core during hot rolling. The pure aluminum cladding acts as a sacrificial anode, corroding preferentially and protecting the high-strength core. Alclad 2024-T3 is one of the most widely used materials in commercial aircraft fuselage construction.
For applications where Alclad is not used, 2024 requires anodizing (typically sulfuric acid or chromic acid anodizing in aerospace, now often replaced by boric-sulfuric acid anodizing for environmental compliance) plus a primed and painted surface system.
7075-T6 is susceptible to stress-corrosion cracking (SCC) in humid or chloride-containing environments. SCC occurs when a susceptible material under sustained tensile stress is exposed to a corrosive environment, causing cracks to propagate at stress levels far below the static yield strength. T6 temper 7075 is among the most SCC-susceptible common aluminum alloys.
The solution is temper selection. 7075-T73 and T7351 are produced by over-aging beyond the T6 peak, which coarsens the grain boundary precipitates and dramatically reduces SCC susceptibility. The trade-off — approximately 12% reduction in tensile strength — is generally acceptable for landing gear, fittings, and structural parts exposed to outdoor environments.
All 7075 components in exterior applications should be anodized and coated. Bare 7075 in humid or marine atmospheres will develop surface pitting within months.
Both 2024 and 7075 are among the most machinable aluminum alloys available. They cut cleanly, hold tight tolerances, and are the default choice for precision aluminum CNC machining across aerospace, defense, and high-performance engineering.
7075 machines slightly faster than 2024. Its higher hardness (approximately 150 HB versus 120 HB for 2024-T3) produces more brittle chips that break cleanly, reducing chip re-cutting and surface damage on long-duration cuts. Surface finishes below Ra 0.4 are routinely achievable on both alloys with standard tooling and coolant.
2024 is somewhat more prone to built-up edge (BUE) on cutting tools, particularly at lower cutting speeds. Using sharp carbide tooling, adequate coolant flow, and appropriate cutting speeds minimizes this effect. For deep-hole drilling and threading, both alloys perform well, though tool life is slightly longer with 7075.
Neither 2024 nor 7075 is recommended for conventional fusion welding (MIG or TIG). Both alloys are susceptible to hot cracking in the weld heat-affected zone, and the welding heat reduces the strength of the age-hardened zone to near-annealed levels. For structural applications requiring welded joints, designers typically use mechanical fasteners (rivets or bolts) as the primary joining method.
Friction stir welding (FSW) is a solid-state process that significantly reduces the hot cracking risk and HAZ strength loss compared to fusion welding. FSW of both 2024 and 7075 is used in aerospace manufacturing — notably in spacecraft fuel tanks and some aircraft structural panels — where it provides weld-zone strength retention of 70 to 90% of parent-metal strength. FSW requires specialized equipment and is a production process rather than a field repair method.
2024-T4 is the specified temper for forming operations: parts are formed in the T4 condition (solution heat-treated and naturally aged, without the cold work of T3), then aged to T3 or T81 after forming. The T4 temper provides sufficient ductility for complex shapes while still allowing final strength to be achieved after the forming operation is complete.
7075 in T6 temper is difficult to form — its high yield strength and limited ductility cause springback and cracking on tight-radius bends. Parts requiring significant forming are produced from 7075-O (annealed) stock and then heat-treated after forming, or from T4 temper where available.
Both 2024 and 7075 aluminum are premium-priced alloys relative to the general-purpose grades discussed in other articles in this series. Both are significantly more expensive than 6061-T6, and considerably more expensive than 3003 or 1100. Here is what drives the cost.
7075 is typically more expensive than 2024 on a per-kilogram basis. The primary reason is zinc content: 7075 contains 5.6 to 6.1% zinc, an element that is more costly than the copper-magnesium combination used in 2024. The price differential varies with market conditions but is generally consistent. Both alloys cost approximately two to three times more per kilogram than 6061-T6, and four to six times more than 3003.
Within each alloy, the temper significantly affects price. For 7075, T651 commands a premium over T6 because of the added stretching operation. T73 and T7351 are priced above T6 because of the additional aging cycle required for the over-aged condition. For 2024, T351 carries a premium over T3 for similar reasons. When comparing quotes for the same alloy, always confirm that the temper is the same before concluding that one supplier is cheaper than another.
Aerospace-grade material — produced and certified to AMS specifications with full material test reports, heat traceability, and certified mechanical properties — carries a significant premium over commercial-grade material of the same alloy and temper. This is not simply a paperwork cost: aerospace-grade production involves tighter process controls, more extensive testing, and full lot traceability from the smelting heat through final inspection.
For aerospace and defense applications where regulatory compliance is required, there is no substitute for AMS-certified material. For non-aerospace applications — UAV hobbyist frames, sporting equipment, general precision machining — commercial-grade 7075-T6 or 2024-T3 is available at meaningfully lower cost and is entirely appropriate.
Thin sheet and foil-gauge material carries a higher processing cost per kilogram than medium-thickness plate. Large-format plate (widths over 1500 mm or thicknesses over 50 mm) may carry a premium for specialty rolling or press capacity. Extruded shapes and bar stock are priced separately from flat-rolled products.
Contact our sales team with your alloy, temper, thickness, width, length, required quantity, and any certification requirements. We will provide current pricing and lead time within 24 hours.
For aviation and defense applications, material certification is not optional. The alloy and temper on the purchase order must match the certification documents, and the documents must trace the material back to its original heat of production.
• 2024 sheet and plate: AMS 2024 (most common aerospace specification), AMS-QQ-A-250/4, ASTM B209
• 7075 sheet and plate: AMS 7075, AMS-QQ-A-250/12, ASTM B209
• Alclad 2024: AMS 2024, Clad (sheet) — requires additional documentation confirming cladding thickness and composition
• Bar, rod, and extruded shapes: separate AMS specifications apply (AMS 2024 covers sheet/plate; AMS 4152 covers bar for 2024; AMS 4122 covers bar for 7075)
• Material Test Report (MTR) / Mill Test Certificate (MTC): must include heat (lot) number, chemical composition analysis, mechanical test results (tensile strength, yield strength, elongation, hardness), and temper verification
• Certificate of Conformance (CoC): supplier certification that material conforms to the specified AMS or equivalent standard
• Heat traceability: aviation regulations (FAA FAR 21, EASA CS-25) require full traceability from the component back to the original production heat
• DFARS compliance: US government contracts typically require aluminum to meet Defense Federal Acquisition Regulation Supplement requirements for domestic melting and production
For UAV frames, sporting equipment, precision machined prototypes, and other non-regulated applications, commercial-grade 7075-T6 or 2024-T3 with a standard mill certificate is sufficient. The AMS premium is only justified when regulatory compliance requires it. If in doubt about your application's certification requirements, consult your quality team or the applicable regulatory body before placing a material order.
Use these criteria to determine the correct alloy before requesting a quote.
• The component is a tension-loaded structural member subject to cyclic fatigue loading (fuselage skin, lower wing skin, pressure bulkheads)
• Damage-tolerant design is required per FAA or EASA regulations, and slow fatigue crack growth rate is a design parameter
• Fracture toughness is critical — the component must tolerate detectable cracks without catastrophic failure
• The part requires forming before final heat treatment (use 2024-T4 for forming, age to T3 or T81 after)
• Alclad surface protection is acceptable and preferred for weight-efficient corrosion protection
• The component is a compression-loaded structure (upper wing skin, wing spars) where static strength governs
• Maximum strength-to-weight ratio is the primary design criterion — UAV frames, precision structural fittings, tooling
• The part will be CNC-machined to tight tolerances from plate stock (use T651 for machined plates)
• High hardness and wear resistance are required alongside strength
• The application is non-aerospace (sporting goods, high-performance consumer products) where the fatigue growth advantage of 2024 is not the governing factor
• The component will be exposed to humid, coastal, or marine atmosphere in sustained tension
• SCC risk must be minimized — landing gear, outdoor structural fittings, fuselage frames in wet zones
• The 12% strength reduction versus T6 is acceptable in the structural analysis
Both 2024 and 7075 are high-cost, specialized alloys. If your application does not require their extreme strength levels, 6061-T6 delivers approximately 310 MPa tensile strength at significantly lower cost and with better weldability, corrosion resistance, and availability. Consider 6061 first for general structural applications before stepping up to 2024 or 7075.
We supply both 2024 and 7075 aluminum in a full range of tempers and product forms, with the material certification documentation that aerospace and defense procurement requires.
• 2024 available in T3, T351, T4, and T81 tempers; sheet, plate, and Alclad sheet
• 7075 available in T6, T651, T73, and T7351 tempers; sheet, plate, bar, and extruded shapes
• AMS-certified material available with full MTR documentation, heat traceability, and CoC
• Commercial-grade material available for non-regulated applications at competitive pricing
• Custom dimensions: specify thickness, width, and length and we cut to order
• Export experience across aerospace supply chains in Asia, the Middle East, Europe, and North America
• Fast RFQ response: provide alloy, temper, form, dimensions, quantity, and certification requirements and we will reply within 24 hours with pricing and lead time
Whether you are procurement for an aircraft manufacturer, sourcing material for a UAV development program, or machining precision structural components for defense applications, we have the alloy, temper, and documentation package to support your program.
Contact us today with your specification. We respond promptly.
