Aluminum 7010: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

7010 is a high-strength aluminum alloy in the 7xxx series, characterized primarily as an Al-Zn-Mg-Cu system. It belongs to the heat-treatable family of aluminum alloys where precipitation hardening (age hardening) produces the principal strengthening, supplemented by appropriate thermo-mechanical processing for plate and thick-section components.

Major alloying elements are zinc (the principal strength contributor), magnesium (forms strengthening precipitates with Zn), and copper (enhances strength and hardness but can affect corrosion susceptibility). Trace additions of chromium, zirconium or titanium are often included to control grain structure, recrystallization, and toughness in coarse sections intended for aerospace structural use.

Key traits of 7010 include very high static strength and good fracture toughness for a 7xxx-series plate alloy, moderate to limited general corrosion resistance without cladding, and poor fusion weldability in peak tempers. Formability is limited in peak-aged conditions but reasonable in solution-treated and overaged tempers; machinability is generally good compared with other high-strength aluminum alloys.

Typical industries using 7010 are aerospace primary and secondary structures, defense components, high-performance automotive and motorsport structural parts, and specialized industrial applications where high strength-to-weight and damage tolerance are imperative. Engineers choose 7010 over similar alloys when the design requires thick-section strength retention, improved resistance to stress-corrosion cracking compared to some 7075 variants, and superior fracture toughness for critical structural parts.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High	Excellent	Excellent	Fully annealed, maximum ductility for forming and machining
T4	Moderate (solution-treated)	Moderate-High	Good	Poor to fair	Solution-treated and naturally aged, ready for cold working
T6	High	Low-Moderate	Limited	Poor	Peak artificially aged for maximum strength
T651	High (stress-relieved)	Low-Moderate	Limited	Poor	T6 with stress relieving by stretching to reduce residuals
T7x (T73/T76)	Moderate-High (overaged)	Moderate	Improved vs T6	Poor	Overaging to improve SCC resistance and toughness
Hxx (e.g., H111/H112)	Variable	Variable	Variable	Variable	Strain-hardened variants used for specific forming workflows

Temper significantly changes 7010 performance by shifting the size, distribution and coherency of Zn-Mg-Cu precipitates. Peak-aged tempers (T6, T651) maximize tensile and yield strength at the expense of ductility, toughness in some geometries, and resistance to stress-corrosion cracking.

Overaged tempers (T7x) intentionally coarsen precipitates to trade a small decrease in peak strength for markedly better SCC resistance and improved crack-growth behavior in thick sections. Annealed or solution-treated conditions are used for forming and fabrication prior to final aging.

Chemical Composition

Element	% Range	Notes
Si	≤ 0.40	Typical impurity; controlled to reduce Fe-Si intermetallics
Fe	≤ 0.50	Impurity that forms hard intermetallics affecting toughness
Cu	0.80–2.00	Raises strength and hardness; increases SCC sensitivity
Mn	≤ 0.05	Minimal in 7010; higher Mn not typical
Mg	1.8–2.8	Key partner with Zn for age-hardening precipitates
Zn	5.6–6.8	Principal strengthening element in the 7xxx series
Cr	0.04–0.35	Microalloying to control grain structure and recrystallization
Ti	≤ 0.15	Grain refiner in cast or wrought processing
Others (Zr, V, Al)	Balance / trace	Zr may be added for dispersoid control; Al balance

The Zn–Mg–Cu combination establishes the precipitation sequence responsible for the high strength of 7010, where η' and η phases (MgZn2-type) provide hardening during artificial aging. Copper elevates peak strength and hardness but increases susceptibility to localized corrosion and SCC unless mitigated by tempering strategies and microalloying (Cr, Zr) that refine grain structure and stabilize the matrix.

Mechanical Properties

7010 exhibits very high ultimate tensile and yield strengths in peak-aged tempers, combined with good fracture toughness relative to other 7xxx alloys engineered for thickness. Yield strength is often a high fraction of UTS, producing tight stress ranges for design but requiring careful notch and fracture assessments for damage-tolerant structures.

Elongation is temper and thickness dependent, with annealed and solution-tempered material showing higher ductility than T6/T651 material which typically has reduced elongation and requires larger bend radii. Hardness correlates strongly with aging condition; peak-aged sections reach typical Vickers/BHN ranges suitable for high-load fittings, while overaged tempers reduce hardness to improve SCC resistance.

Fatigue performance of 7010 is favorable when compared to many high-strength Al alloys, provided surface finish, residual stresses, and corrosion are controlled. Thickness effects are significant due to quench sensitivity and centerline precipitate distribution; thicker plates require optimized quenching and thermo-mechanical processing to approach sheet-level properties.

Property	O/Annealed	Key Temper (e.g., T6 / T651)	Notes
Tensile Strength	~250–320 MPa	~540–610 MPa	T6/T651 peak ranges depend on product form and thickness
Yield Strength	~120–200 MPa	~480–560 MPa	Yield to UTS ratios vary; careful design for plastic margins
Elongation	~12–20%	~6–12%	Higher in thin gauges and annealed conditions
Hardness	~60–90 HB	~150–185 HB	Hardness increases with aging; overaging reduces values

Physical Properties

Property	Value	Notes
Density	2.78–2.82 g/cm³	Typical Al alloy density; good strength-to-weight
Melting Range	~475–635 °C	Solidus-liquidus range depends on composition
Thermal Conductivity	~110–140 W/m·K	Lower than pure Al due to alloying; adequate for some heat-sink use
Electrical Conductivity	~30–40 %IACS	Reduced vs 1xxx/3xxx series due to alloying
Specific Heat	~880–910 J/kg·K	Comparable to other Al alloys
Thermal Expansion	~23–24 µm/m·K (20–100 °C)	Typical aluminum range; design for thermal mismatch needed

7010’s physical properties reflect its alloying for strength rather than conductivity, so electrical and thermal conductivities are reduced compared to commercial-purity grades. The density advantage over steels combined with high tensile properties makes 7010 attractive where mass saving is critical.

Thermal treatments and aging affect thermal conductivity and expansion slightly, but dimensional stability is primarily managed by temper (T651 vs T6) and by minimizing residual stresses through controlled cooling and stress-relief operations.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.5–6 mm	High in thin gauges when properly aged	T6, T651, T73	Used for secondary structures; formability limited in peak tempers
Plate	6–200+ mm	Thickness-dependent strength; processed for through-thickness properties	T6, T651, T73	Widely used in aerospace structural components
Extrusion	Profiles up to large cross-sections	Strength moderate; limited compared to plate for some shapes	T6, T651	Extruded sections possible but less common for 7010 than for 6xxx alloys
Tube	1–50+ mm wall / various diameters	Similar temper behavior to extrusions	T6, T651	Used in high-performance tubing where strength is critical
Bar/Rod	Various diameters	Good machinability and high strength in peak tempers	T6, T651	Used for fittings, fasteners and actuated components

Plate production for 7010 involves specific rolling and quench schedules and often microalloying to avoid quench-induced centerline softening. Sheet/extrusion processing requires careful control of solution treatment and aging to balance formability with final properties.

In service, designers select product form based on section thickness and load path; thick plates are often overaged or stress-relieved to avoid SCC and provide more uniform properties through thickness while thinner sheets can be utilized in higher strength tempers with acceptable ductility.

Equivalent Grades

Standard	Grade	Region	Notes
AA	7010	USA	Aluminum Association designation commonly used in aerospace specifications
EN AW	7010	Europe	European wrought designation; composition and tempers aligned but spec limits may differ
JIS	A7070 (approx.)	Japan	Close chemistry and application space; specific JIS numbers may vary by product form
GB/T	7010 (approx.)	China	National standards mirror AA compositions but processing and temper nomenclature can differ

Equivalent-grade tables are indicative; the exact specification, temper designation and allowable tolerances vary between standards and product types. Users must consult the specific standard (AA/AMS/EN/JIS/GB) and product specification for acceptance criteria, especially for aerospace procurement where traceability and processing history are mandatory.

Subtle differences arise in impurity limits, allowed residual elements, and mandated mechanical testing. These differences can shift property baselines, particularly in thick-section plate where quench and aging behavior is more sensitive to composition and thermomechanical history.

Corrosion Resistance

7010 offers moderate general atmospheric corrosion resistance typical of high-strength 7xxx alloys, but it is more susceptible to localized corrosion and pitting in aggressive environments than many 5xxx or 6xxx alloys. Without protective cladding, coatings, or appropriate overaged tempers, exposures to marine atmospheres accelerate corrosion rates, especially at stressed or machined surfaces.

Stress-corrosion cracking (SCC) is a primary concern for 7010 in peak-aged conditions due to high residual tensile stresses and the nature of the strengthening precipitates. Overaging (T7x) and microalloying (Cr, Zr) are common strategies to mitigate SCC by coarsening or redistributing precipitates and reducing electrochemical gradients.

Galvanic interactions must be considered when joining 7010 to more noble materials such as stainless steel or titanium, particularly in the presence of electrolyte. Cladding with pure aluminum or applying conversion coatings, anodizing, or paint systems are standard engineering controls to improve long-term performance in marine and coastal applications.

Compared with 6xxx-series alloys, 7010 trades corrosion resistance for higher strength; compared with 7075, well-processed 7010 plate can offer similar strength with improvements in SCC resistance due to tailored chemistries and thermomechanical processing aimed at thick-section performance.

Fabrication Properties

Weldability

Welding conventionally reduces strength in 7010 due to HAZ softening and promotes hot-cracking susceptibility in fusion welds; as a result, fusion welding (TIG/MIG) is generally discouraged for structural applications in peak tempers. Friction stir welding is the preferred joining method for many 7xxx components because it avoids fusion solidification, reduces porosity, and can retain favorable mechanical properties in the weld zone with proper post-weld aging.

Filler metals and welding procedures that attempt to weld 7010 must be chosen with caution; dissimilar fillers (e.g., 2319 family) may be used for repair or non-critical joints, but designers should account for local loss of mechanical properties and increased corrosion susceptibility. Post-weld solution treatment and artificial aging are often impractical for large assemblies, so mechanical fastening remains common.

Machinability

Machinability of 7010 is good relative to many high-strength aluminum alloys, offering predictable chip formation and good surface finishes when using carbide tools and rigid setups. Cutting speeds should be optimized for tool life and thermal management; high-speed steel is typically insufficient at high removal rates.

Achieving acceptable dimensional tolerances in thick sections requires consideration of residual stresses from heat treatment; pre-stress relief and temper selection for machining are common practices. Coolant and chip evacuation are important to avoid built-up edge and to maintain fatigue-critical surface integrity.

Formability

Forming 7010 in peak tempers is limited; springback is pronounced and minimum bend radii are larger compared with 5xxx and 6xxx alloys. Forming is typically performed in O, T4, or overaged tempers and followed by aging if necessary to restore strength.

Cold-forming operations should respect recommended bend radii (often 3–6× thickness in ductile tempers) and avoid sharp bends or severe drawing in T6. When complex shapes are required, consider designing for post-form heat treatment (solutionize and age) or using alternative alloys with superior formability.

Heat Treatment Behavior

Solution treatment for 7010 is generally conducted in the range of approximately 470–485 °C to dissolve soluble Zn–Mg–Cu phases into the aluminum matrix prior to quenching. Rapid quenching (typically water quench) is required to retain a supersaturated solid solution; quench rates and section thicknesses significantly influence the subsequent age-hardening response and centerline properties.

Artificial aging regimens vary depending on the target temper: standard T6 involves aging at about 120–125 °C for times sufficient to precipitate metastable η' phases that yield peak strength, while T7x overaging uses higher temperature or longer cycles to promote stable η precipitates that improve SCC resistance and toughness. T651 denotes T6 followed by a controlled stretching operation to relieve residual stresses.

For non-heat-treatable alloys the principal strengthening mechanism is work hardening, but because 7010 is heat-treatable, annealing and solution treatment routes are the primary fabrication tools. Design and process engineers must specify precise heating, soak times, cooling media, and aging cycles to achieve required properties, especially for thick plates where quench sensitivity is a limiting factor.

High-Temperature Performance

7010 loses substantial strength as service temperature increases above roughly 100–120 °C due to precipitate coarsening and reduction of coherent strengthening phases. Design service limits for sustained elevated temperatures are conservative; short-term exposure to higher temperatures is possible but will alter aging state and residual strength.

Oxidation resistance is typical for aluminum alloys; a stable aluminum oxide forms and protects bulk material from rapid oxidation. The heat-affected zones in welded or thermally cycled parts can experience localized microstructural changes that reduce mechanical properties and increase susceptibility to corrosion, so thermal exposure during fabrication and service must be controlled.

Applications

Industry	Example Component	Why 7010 Is Used
Aerospace	Wing and fuselage fittings, spar webs, thick plate structures	High strength-to-weight, good fracture toughness, tailored thickness performance
Defense	Armor components, missile structures	High static strength and damage tolerance
Automotive / Motorsport	High-stress suspension links, chassis reinforcements	Exceptional strength for weight-critical parts
Marine	High-strength structural members, frames	When overaged or clad, offers better SCC resistance than some 7xxx alloys
Industrial	High-load shafts, tooling plates	Dimensional stability and machinability in T6/T651 tempers

7010 is selected for components where a premium is placed on high static strength, thickness-capable performance, and fracture toughness. Parts that require welding are a less suitable fit unless alternative joining approaches are employed, so many applications favor mechanical fastening or friction stir welding.

Selection Insights

7010 is a specialist alloy chosen when high strength and damage tolerance in medium to thick sections are priorities. For designers needing the highest possible strength in non-welded, load-bearing structural elements—especially in aerospace and defense—7010 is often a first choice due to its tailored chemistries and temper options.

Compared with commercially pure aluminum (1100), 7010 sacrifices electrical and thermal conductivity and formability for dramatically higher tensile and yield strengths. Compared with work-hardened alloys such as 3003 or 5052, 7010 provides significantly higher strength but at the cost of reduced formability and increased susceptibility to SCC in peak tempers.

Compared with common heat-treatable alloys like 6061 or 6063, 7010 typically offers higher peak strength and better fracture toughness for thick sections, though at higher material cost and lower weldability. Choose 7010 when strength-to-weight and thick-section integrity outweigh requirements for easy welding, broad formability, and maximum corrosion resistance.

Closing Summary

7010