Aluminum 2007: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

2007 is a member of the 2xxx series aluminum alloys, a family dominated by copper as the principal alloying element. Alloys in this series are categorized as heat-treatable aluminium-copper(-magnesium/manganese) alloys and are designed to achieve high strength through precipitation hardening rather than by work-hardening alone.

The major alloying elements in 2007 are copper (primary strengthening element), with controlled additions of magnesium and manganese for precipitation kinetics and grain structure control; iron, silicon, chromium and titanium typically appear as controlled impurities or microalloying additions. The strengthening mechanism is classic age-hardening: solution heat treatment, quench and artificial aging produce fine theta (Al2Cu) and associated precipitates that raise yield and ultimate tensile strengths significantly.

Key traits of 2007 include elevated strength-to-weight ratio, moderate machinability and fair thermal conductivity compared with other 2xxx alloys. Corrosion resistance is inferior to 5xxx and 6xxx series alloys and weldability is limited without special filler selection and post-weld treatments; formability is good in annealed and naturally aged tempers but deteriorates as strength is increased by artificial aging.

Industries that use 2007 typically include aerospace substructures and fittings where high strength and fatigue resistance are required, defence and weapon systems for structural components, and specialty automotive applications where localized strength improvement is necessary. Engineers select 2007 when a combination of relatively high static and fatigue strength is required without the premium cost or processing complexity of more exotic aluminium-lithium or high-strength 7xxx alloys.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High	Excellent	Excellent	Fully annealed condition, maximum ductility for forming
H14	Medium	Low–Moderate	Poor–Fair	Moderate	Strain-hardened to moderate strength; limited bendability
T4	Medium	Moderate	Good	Moderate	Solution-treated and naturally aged; balances strength and formability
T5	Medium–High	Low–Moderate	Fair	Moderate	Cooled from an elevated temperature processing and artificially aged
T6	High	Low	Poor–Fair	Challenging	Solution-treated and artificially aged to peak strength
T651	High	Low	Poor–Fair	Challenging	T6 with stress-relief stretching to minimize residual stresses

The temper selected for 2007 strongly controls the trade-off between strength and ductility. Annealed (O) and naturally aged (T4) tempers enable deep drawing and complex forming, while artificially aged (T5/T6/T651) tempers deliver the highest static and fatigue strengths at the expense of bendability and springback control.

Heat and mechanical treatments also affect weldability and residual stress. Higher-strength tempers tend to soften in the heat-affected zone (HAZ) and may require post-weld aging or local reinforcement to restore load-carrying capacity.

Chemical Composition

Element	% Range	Notes
Si	≤ 0.5	Controlled silicon to limit casting/feeding phases; higher Si reduces ductility
Fe	≤ 0.5	Iron is an impurity; excessive Fe forms brittle intermetallics
Mn	0.3–1.0	Grain structure control, dispersoid former; improves toughness and recrystallization behavior
Mg	0.2–1.0	Assists precipitation hardening and strength when combined with Cu
Cu	3.5–5.0	Principal strength-providing element through Al2Cu precipitation
Zn	≤ 0.25	Minor; higher levels not typical for 2xxx series
Cr	≤ 0.25	Microalloying to control grain growth and reduce quench sensitivity
Ti	≤ 0.15	Grain refiner when intentionally added
Others (each)	≤ 0.05–0.15	Trace elements and balancing aluminium to 100%

The balance is aluminium with the listed elements tailored to meet mechanical and processability targets. Copper content directly governs peak age-hardening response and ultimate attainable strength, while magnesium and manganese fine-tune precipitation kinetics and the alloy’s resistance to recrystallization during thermomechanical processing.

Mechanical Properties

When processed to peak-aged tempers (T6/T651), 2007 exhibits high ultimate tensile and yield strengths comparable with other high-strength 2xxx alloys. Tensile curves typically show a pronounced yield plateau or gradual strain hardening dependent on temper and product form. Elongation is inversely proportional to strength; peak-aged sheet or plate commonly exhibits reduced elongation compared with annealed condition.

Hardness correlates with age-hardening and is a practical control metric during production; Rockwell or Brinell hardness increases markedly from the annealed to the T6 condition. Fatigue behaviour is generally favorable when compared to lower-strength alloys in the same product form, but fatigue life is sensitive to surface condition, local stress concentrations and corrosion environment. Thickness and product form also influence mechanical properties through quench rate sensitivity; heavier sections may achieve lower peak properties and experience greater quench-induced residual stresses.

Property	O/Annealed	Key Temper (T6 / T651)	Notes
Tensile Strength (MPa)	180–260	400–480	Peak values depend on section thickness and aging cycle
Yield Strength (MPa)	70–140	300–370	0.2% offset yield; influenced by work history and temper
Elongation (%)	20–35	8–15	Higher in O/T4; T6 tempers trade elongation for strength
Hardness (HB)	35–80	110–160	Brinell ranges; hardness correlates to precipitate distribution

Physical Properties

Property	Value	Notes
Density	2.78 g/cm³	Typical for Al-Cu alloys; slightly higher than pure aluminium due to alloying
Melting Range	~500–650 °C	Solidus/liquidus vary with local composition and impurities
Thermal Conductivity	120–160 W/m·K	Lower than purer aluminium due to copper and other solutes
Electrical Conductivity	25–40 %IACS	Reduced conductivity relative to 100% Al; varies with temper and cold work
Specific Heat	~880–900 J/kg·K	Approximate value near ambient temperature
Thermal Expansion	22–24 µm/m·K	Coefficient in the range common for aluminium alloys

The physical properties reflect the compromise between adding high levels of copper for strength and retaining usable thermal and electrical performance. Thermal conductivity remains substantially higher than steels, which supports thermal management applications, but the conductivity penalty relative to 6xxx or 1xxx alloys should be considered in designs requiring maximum heat transfer.

Thermal expansion is similar to other aluminium alloys, making 2007 compatible with aluminium-based assemblies but requiring design consideration when mated to dissimilar materials. Melting and solidus ranges require controlled welding and brazing practice to avoid localized melting and grain boundary liquation.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.3–6.0 mm	Good in thin gauge; quench sensitivity less critical	O, T4, T6	Widely used for formed components and panels
Plate	6–100+ mm	Strength may be reduced in thick sections due to slow quench	T4, T6	Thick plates require controlled quenching and possible post-aging
Extrusion	Cross-sections variable	Mechanical properties depend on section thickness and solution treatment	T4, T5, T6	Extrusions allow complex profiles; control of precipitate distribution is critical
Tube	OD and wall vary	Similar to extruded properties; HAZ and distortion must be managed	O, T4, T6	Seamless or welded tubes used in structural members
Bar/Rod	≤ 200 mm diameter	Generally good longitudinal properties; aging uniformity matters	O, T4, T6	Used for forged or machined components

Different product forms impose different constraints on heat treatment and quench rates. Thin sheet and small extruded sections can be rapidly quenched and reach peak-aged strengths reliably, while thick plate or large-section extrusions may require interrupted quenching, lower peak strength targets, or extended artificial aging to achieve balanced properties throughout the cross section.

Processing routes also determine final application fit: sheet and plate are frequently used where stamping and forming are necessary prior to final aging, while extrusions and bars are commonly solution-treated/aged to exploit directional mechanical behavior. Welding of different product forms may require filler selection and local heat management to minimize HAZ softening.

Equivalent Grades

Standard	Grade	Region	Notes
AA	2007	USA	Recognised in aluminium alloy classification; compositions may vary with subvariants
EN AW	2007 (or 2xxx series)	Europe	Often listed under EN AW-2007 or EN AW-2xxx family; check national datasheets
JIS	A2007 (or similar)	Japan	Japanese standards may present near-equivalent alloys with slightly different impurity limits
GB/T	2007	China	Chinese industrial designations include 2007 and 2007A variants; chemistry tolerances may differ

Exact equivalents depend on the specific variant and the controlling specification; some regions list 2007A or 2007S with subtle differences in copper, magnesium and manganese limits. When substituting across standards, verify mechanical properties, heat-treatment schedules and allowable impurity levels rather than relying solely on grade name.

Corrosion Resistance

Atmospheric corrosion resistance for 2007 is moderate to poor relative to non-heat-treatable series; copper increases susceptibility to general and localised corrosion when compared with 5xxx and 6xxx alloys. Protective coatings, cladding (e.g., Alclad) or conversion treatments are commonly employed to mitigate environmental attack in exterior applications.

Marine exposure is a concern: high-salinity environments accelerate pitting and crevice corrosion in copper-bearing alloys, and unprotected 2007 is not typically recommended for primary hull structural members in marine atmospheres. Cathodic protection and isolating materials to avoid galvanic couples are common countermeasures where 2007 must be used near other metals.

Stress corrosion cracking (SCC) can be an issue for high-strength 2xxx alloys under tensile stress in corrosive chloride-containing environments. The combination of tensile residual stresses, susceptible microstructure and aggressive media promotes intergranular attack and SCC; design practice usually avoids sustained high tensile stresses in corrosive environments or specifies protective measures.

Galvanic interaction with dissimilar metals must be managed: 2007 paired with stainless steels may be acceptable if electrically insulated, but contact with more noble metals without insulation will promote aluminium dissolution. Relative to other alloy families, 2007 offers superior strength but requires more aggressive corrosion protection strategies than 5xxx and 6xxx series aluminium alloys.

Fabrication Properties

Weldability

Welding 2007 requires caution because high copper content increases hot-cracking susceptibility and reduces as-welded strength in the HAZ. Common practice is to avoid full-penetration structural welds where possible; if welding is necessary, use filler alloys designed for Al-Cu systems (for example Al-Cu-Mn fillers such as 2319) and control heat input and pre/post-heat treatments. Expect HAZ softening in T6 and similar tempers; post-weld solution treatment and re-aging or local reinforcement may be required to restore parent-metal performance.

Machinability

Machinability of 2007 is generally good relative to many aerospace aluminium alloys due to its relatively high strength and controlled chip formation; it machines more cleanly than some high-silicon alloys but is not as free-cutting as 2xxx free-machining variants. Carbide tooling with positive rake and ample coolant are recommended; typical finishes are achievable at moderate to high cutting speeds, with feeds chosen to produce short, controllable chips and to avoid built-up edge.

Formability

Forming performance depends strongly on temper: O and T4 tempers offer the best bendability and drawability, while T6 and strain-hardened tempers have limited room-temperature formability. Minimum bend radii should be based on temper and thickness; as a general guideline, annealed sheet can accept radii down to 1–2× thickness for many operations, whereas T6 may require larger radii or warm forming to avoid cracking. Incremental bending and proper tooling radii help mitigate local cracking in higher-strength tempers.

Heat Treatment Behavior

As a heat-treatable alloy, 2007 responds to classic solution treatment and aging cycles. Solution heat treatment is typically performed in the range of 495–520 °C (dependent on section size and specific variant) to dissolve copper-bearing phases into the matrix, followed by rapid quench to retain a supersaturated solid solution. Quench rate is critical: insufficient quenching allows coarse precipitates to form, reducing the attainable peak strength and increasing quench sensitivity in thicker sections.

Artificial aging for T6 temper commonly uses temperatures in the range of 150–190 °C for times that depend on section thickness and desired property balance; lower temperature longer-time treatments reduce quench sensitivity and improve toughness at the expense of slightly lower peak strength. T4 (natural aging) delivers moderate strength and better formability by allowing controlled room-temperature precipitation; T5 is used when components are cooled from elevated-temperature processing and then aged to a specified hardness.

For non-heat-treatable processing (strain hardening), control of cold work and annealing temperatures is used to set interim properties. Annealing cycles fully soften the material to the O temper, enabling forming operations prior to final age-hardening for peak performance.

High-Temperature Performance

2007 loses strength progressively with increasing temperature as precipitates coarsen and the matrix softens; service temperatures above approximately 120–150 °C will reduce yield and tensile strength significantly compared with ambient conditions. For short-term exposure or intermittent service up to ~200 °C some properties may be retained, but prolonged exposure at elevated temperature accelerates over-aging and microstructural coarsening.

Oxidation resistance is typical of aluminium alloys — a protective Al2O3 film forms rapidly at elevated temperatures — but internal microstructural instability rather than surface oxidation is the limiting factor for mechanical performance. HAZ behavior during elevated-temperature processing or welding requires attention, as local softening may create stress concentrations and reduce fatigue life.

Applications

Industry	Example Component	Why 2007 Is Used
Aerospace	Fittings, brackets, subframes	High strength-to-weight and fatigue resistance for critical fittings
Automotive	Structural reinforcements, chassis components	Localized high-strength where weight reduction is required
Marine	Specialized structural fittings (coated)	Good strength when protected; used in non-critical marine hardware
Defence	Weapon housings, structural parts	High static strength and machinability for precision parts
Electronics	Heat spreaders, mechanical supports	Thermal conductivity and stiffness combined with machinability

2007 tends to be chosen for components requiring a higher strength envelope than common 6xxx alloys while retaining aluminium’s low density and machinability. Protective treatments and design allowances are typically incorporated when corrosion exposure is expected.

Selection Insights

Use 2007 when your design prioritizes high strength and fatigue resistance in aluminium with acceptable machining characteristics, and when you can control corrosion exposure via coatings or cladding. It is most suitable where age-hardening is desired to reach a specific strength target after forming or machining.

Compared with commercially pure aluminium (1100), 2007 sacrifices electrical and thermal conductivity and formability for substantially higher strength and better fatigue performance. Compared with work-hardened alloys such as 3003 or 5052, 2007 delivers markedly higher peak strength but requires stricter corrosion protection and is less suitable for deep drawing in the T6 condition. Compared with common heat-treatable alloys like 6061 or 6063, 2007 offers higher strength in many tempers but poorer corrosion resistance and more demanding welding behavior; choose 2007 when strength and fatigue outweigh weldability and corrosion trade-offs.

Closing Summary

2007 remains relevant where aluminium’s low density must be combined with elevated strength and fatigue performance, particularly in aerospace, defence and selective automotive applications. Effective use of 2007 depends on careful temper selection, controlled heat treatment and corrosion protection strategies to balance its high-strength advantages against its weldability and environmental susceptibility.