Aluminum 2014: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

Alloy 2014 is a member of the 2xxx series of wrought aluminum-copper alloys, where copper is the principal alloying element used to raise strength through precipitation hardening. It is a heat-treatable alloy that responds strongly to solution treatment, quenching and artificial aging to develop high strength relative to many other aluminum families.

Major alloying elements are copper (typically ~3.9–5.0 wt%), with lesser additions of manganese, magnesium and chromium to control grain structure and strength. The alloy achieves its mechanical performance via the formation of fine Al2Cu (θ) precipitates during aging, combined with cold work where applicable, producing high tensile and yield strengths at the expense of some ductility and corrosion resistance.

Key traits include very high strength for a wrought aluminum alloy, moderate-to-poor corrosion resistance in aggressive environments, limited weldability without special procedures, and moderate formability in softer tempers. Typical industries using 2014 are aerospace for structural fittings and forgings, defense and military hardware, high-strength components in transportation, and specialist machining applications where high strength-to-weight ratios are critical.

Designers choose 2014 when strength and fatigue resistance (in a heat-treated condition) are prioritized over forming ease and raw conductivity, or when a combination of high static strength and machinability is required. The trade-offs are lower generalized corrosion resistance and reduced weld performance compared with 5xxx and 6xxx series alloys, which makes selection context-dependent.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High	Excellent	Excellent	Fully annealed; easiest to form and bond, lowest strength
H14	Medium	Moderate	Good (limited)	Challenging	Strain-hardened; moderate strength via cold work
T5	Medium-High	Moderate-Low	Fair	Poor-Moderate	Cooled from hot working and artificially aged; good dimensional stability
T6	High	Low	Limited	Poor	Solution heat-treated and artificially aged; peak strength
T651	High	Low	Limited	Poor	T6 with stress-relief by stretching; common for aerospace forgings

The temper designation has a major impact on 2014’s mechanical and fabrication behavior: annealed (O) material is ductile and readily formed while T6/T651 conditions maximize strength at the cost of elongation and formability. Welding and high-heat joining procedures are more likely to create soft zones and microstructural changes in peak-aged tempers, so design and post-weld treatments must be planned accordingly.

Chemical Composition

Element	% Range	Notes
Si	≤ 0.5	Minor impurity; low Si helps maintain toughness
Fe	≤ 0.7	Common impurity; excessive Fe can form intermetallics that reduce ductility
Mn	0.4–1.2	Refines grain structure and improves strength/toughness
Mg	0.2–0.8	Contributes to age-hardening in concert with Cu
Cu	3.9–5.0	Primary strengthening element (forms Al2Cu precipitates)
Zn	≤ 0.25	Minor; higher Zn not typical for 2xxx series
Cr	0.1–0.4	Controls recrystallization and grain growth during thermal processing
Ti	≤ 0.15	Grain refiner for cast and wrought products
Others	≤ 0.15 (each)	Includes trace elements and residuals; Al balance

Copper is the critical element driving the alloy’s age-hardening response via formation of finely dispersed Al2Cu precipitates. Manganese and chromium act primarily as microalloying additions to control grain structure and mitigate softening during thermal exposure. The combination of these elements provides a balance between hardenable microstructure and machinability while reducing some of the corrosion resistance associated with purer aluminum alloys.

Mechanical Properties

In tensile behavior the alloy shows a strong dependence on temper: annealed 2014 (O) exhibits ductile tensile curves with modest ultimate tensile strength (UTS), whereas T6/T651 displays high UTS and pronounced yield strengths. Elongation to failure drops significantly in peak-aged states, typically moving from mid-double-digit percent elongation in O to single-digit values in T6. Thickness and prior processing (extrusion, rolling, forging) further influence work-hardening behavior and residual strength gradients through the cross section.

Hardness follows the same trend as tensile properties, with Brinell or Rockwell hardness readings substantially higher in T6/T651 than O or H tempers. Fatigue performance of 2014 in T6 is generally good for aluminum alloys when surfaces are well-finished and compressive residual stresses are present; however, corrosion-fatigue and stress-corrosion cracking susceptibility can limit fatigue life in service environments. Thicker sections can retain higher retained strength in service, but build-up of residual stresses and microstructural inhomogeneity can also affect fracture toughness and crack propagation behavior.

Property	O/Annealed	Key Temper (T6/T651)	Notes
Tensile Strength (UTS)	180–260 MPa	420–480 MPa	UTS increases substantially on solution and aging
Yield Strength (0.2% offset)	70–150 MPa	340–410 MPa	Yield strength in T6 approaches mid/high hundreds MPa
Elongation (A%)	20–30%	4–10%	Ductility is traded off for strength in heat-treated tempers
Hardness (HB)	40–70 HB	120–150 HB	Hardness correlates with precipitate density and temper

Physical Properties

Property	Value	Notes
Density	2.78 g/cm³	Typical for Al-Cu wrought alloys
Melting Range	Solidus ~500–515°C; Liquidus ~635–645°C	Alloying shifts solidus downward compared with pure Al
Thermal Conductivity	~120–150 W/m·K	Lower than pure Al due to alloying; depends on temper and grain state
Electrical Conductivity	~30–40 % IACS	Reduced by copper and other solutes compared with pure Al
Specific Heat	~880 J/kg·K (0.88 J/g·K)	Typical aluminum-range specific heat
Thermal Expansion	~23.5–24.0 µm/m·K	Coefficient similar to other Al alloys; design for differential expansion needed

The physical properties reflect the compromise introduced by alloying for strength. Thermal and electrical conductivities are substantially reduced from those of pure aluminum, so 2014 is not typically chosen for principal conductor or highest-performance heat sink roles unless mechanical strength is the overriding constraint. Density remains low compared to steels, giving a high specific strength that is valuable in aerospace and transport applications.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.3–6.0 mm	Rolling can produce strong, uniform properties	O, H14, T3, T6	Thin-gauge sheet used where machining follows forming
Plate	6–100+ mm	Thick sections sensitive to quench rate and residual stresses	T6, T651	Thick plate requires careful solution treatment and quench control
Extrusion	Cross-sections to several hundred mm²	Extrusion flow affects precipitate distribution	O, T5, T6 (after heat treatment)	Complex profiles possible but heat treating thicker extrusions is complex
Tube	OD up to a few hundred mm	Welding and seam quality important for pressure applications	O, T6	Drawn or welded tubes; strength varies with wall thickness
Bar/Rod	Diameters 5–200 mm	Machinability and strength balance for fasteners/forgings	O, T6, T651	Common for machined components and forged fittings

Form affects achievable properties: thinner products cool faster during quenching, enabling more complete retention of supersaturated solute and thus higher response to artificial aging. Plate and heavy forgings are more sensitive to section size and quench rates, frequently requiring T651 (stretched and aged) to manage residual stresses. Extruded and drawn shapes can be processed to near-final geometry before heat treatment to control distortion during quench and age cycles.

Equivalent Grades

Standard	Grade	Region	Notes
AA	2014	USA	The American Aluminum Association designation commonly used in specifications
EN AW	2014	Europe	EN AW-2014 corresponds to AA2014 with similar composition and tempers
JIS	A2014	Japan	Japanese designation A2014 aligns closely with AA2014 standards
GB/T	2A14	China	Chinese standard 2A14 approximates AA2014 chemical and mechanical limits

Equivalency across standards is generally close in chemical specification and temper designations, but allowable tolerances, testing procedures and mechanical property limits can differ slightly. Purchasers should verify temper processing (for example slight differences in T6 vs T651 acceptance criteria) and acceptance testing between standards when sourcing internationally to avoid mismatches in property expectations.

Corrosion Resistance

In atmospheric service 2014 exhibits moderate corrosion resistance; it performs acceptably in protected, mildly corrosive environments but is inferior to Al-Mg alloys like 5xxx series and to Al-Mg-Si 6xxx alloys. The high copper content increases galvanic activity and local cell formation, making painted or cladded protection advisable for prolonged outdoor exposure. Surface treatments, cladding (e.g., Alclad), and inhibitory coatings are common to mitigate generalized corrosion.

In marine or chloride-rich environments alloy 2014 is more susceptible to pitting and crevice corrosion compared with 5xxx and 6xxx alloys. Stress-corrosion cracking (SCC) is a concern for copper-bearing 2xxx series alloys under tensile stress and corrosive media; peak-aged tempers (T6/T651) are particularly vulnerable and require conservative design and inspection in aggressive environments. Protective design, material selection, and cathodic/anodic considerations are necessary when 2014 is specified for marine-adjacent hardware.

Galvanic interactions should be considered since 2014 (with higher open-circuit potential due to copper) will tend to be cathodic to many pure aluminum alloys and anodic to stainless steels depending on electrolyte. When paired with dissimilar metals, isolating materials and using compatible fasteners or protective coatings reduces risk. Compared with 7xxx series high-strength alloys, 2014 generally has better toughness but similar or marginally worse corrosion behavior, so selection often depends on the full trade-off set of strength, corrosion resistance and fabrication requirements.

Fabrication Properties

Weldability

Welding of 2014 is challenging due to its high copper content and precipitation-hardened microstructure; fusion welding (MIG/TIG) commonly produces softening in the heat-affected zone (HAZ) and can produce hot-cracking in poorly controlled conditions. Recommended practice for welded assemblies often favors mechanical fastening or adhesive bonding; when welding is required, specialized filler alloys and pre/post-heat treatments are used to restore properties. Resistance welding and brazing can be alternative joining routes, but each method requires qualification for SCC and corrosion performance.

Machinability

Alloy 2014 is considered one of the more machinable high-strength aluminum alloys; in T6 and T651 tempers it machines cleanly with high surface finish and good dimensional control. Tool steels such as carbide or coated carbide are commonly used at moderate cutting speeds with positive rake geometries to manage chip flow and avoid built-up edge. The alloy’s relatively low work hardening and stable chips aid productivity, but coolant and chip evacuation are important to preserve tool life and surface integrity.

Formability

Formability is best in the O and softer H tempers; peak-aged tempers have limited bendability and require greater radii to avoid cracking. Typical recommended minimum internal bend radii for T6 sheet are on the order of 3–6× thickness depending on direction and tooling, whereas O temper can approach 1–3× thickness in many cases. Warm forming and incremental forming techniques can improve outcomes, but designers should prefer forming prior to final heat treatment when high strength is required.

Heat Treatment Behavior

As a heat-treatable alloy, 2014 is processed by solution treatment, quenching and artificial aging to develop peak strength. Typical solution treatment temperatures are around 495–505°C (dependent on section size) where copper-bearing phases dissolve into a supersaturated solid solution; rapid quenching to room temperature is necessary to retain the solute in solution prior to aging. Improper quench rates in thick sections can produce inhomogeneous properties due to partial precipitation during cooldown.

Artificial aging (T6) is usually accomplished at temperatures between approximately 160–190°C for several hours to precipitate Al2Cu and associated phases to a fine distribution that maximizes strength. The T5 temper (cooled from hot working and artificially aged) provides good dimensional stability without a full solution treatment. T651 indicates solution heat-treated, stress-relieved by stretching and then artificially aged for improved straightness and reduced residual stress; this is common in aerospace and precision machined parts.

Overaging reduces strength but can improve toughness and corrosion resistance; designers sometimes specify sub- or over-aged tempers when SCC or stress relaxation is a concern. Because the HAZ of welded zones is softened by solutioning and aging reactions, post-weld heat treatment or mechanical repair is often required to regain original mechanical performance.

High-Temperature Performance

2014 loses tensile and yield strength progressively with increasing temperature as precipitates coarsen and the solid solution softens; useful strength is substantially reduced above ~150–200°C depending on temper and time at temperature. Long-term exposure to elevated temperature can cause significant overaging and loss of mechanical integrity, limiting continuous service temperature to moderate ranges for structural applications.

Oxidation of aluminum alloys at elevated temperatures is comparatively mild compared with steels, but protective oxide films can be compromised by alloying elements and thermal cycling. The HAZ adjacent to welds experiences microstructural changes during thermal excursions which can make crack initiation sites more likely under cyclic or mechanical loading. For high-temperature structural needs, specialty alloys with better elevated-temperature retention are typically chosen over 2014.

Applications

Industry	Example Component	Why 2014 Is Used
Aerospace	Fittings, forgings, wing ribs	High strength-to-weight and good fatigue performance in T6/T651
Automotive	High-strength machined brackets, structural inserts	Strength and machinability for safety-critical components
Defense	Armor fittings, weapon mounts	High static strength and durability under load
Electronics	Structural frames and high-strength housings	Dimensional stability and machinability for precision parts

2014 remains valuable where high-strength wrought aluminum is required and where machined finish, dimensional stability and fatigue resistance are more important than superior corrosion resistance. Its combination of age-hardenability and good machinability makes it a workhorse for precision structural components, particularly in aerospace and defense sectors.

Selection Insights

Use 2014 when the design prioritizes high yield and tensile strength combined with good machinability and when post-form heat treatment or tight dimensional control is acceptable. Specify O or H tempers only when significant forming is required prior to final aging or machining.

Compared with commercially pure aluminum (e.g., 1100): 2014 trades electrical and thermal conductivity and ease of forming for substantially higher strength and fatigue resistance. Compared with common work-hardened alloys (e.g., 3003 / 5052): 2014 offers much higher peak strength but typically worse corrosion resistance and marginally more difficult forming. Compared with common heat-treatable alloys (e.g., 6061 / 6063): 2014 often provides higher strength in T6/T651 for specific applications, but at the cost of reduced weldability and corrosion resistance; choose 2014 when strength and machinability outweigh these penalties.

Practical selection considerations: evaluate operating environment (corrosion and SCC risk), required joining/fabrication routes (welding vs mechanical fastening), and whether post-fabrication heat treatment or cladding is feasible. For global sourcing, confirm temper and standard equivalences to ensure the delivered material meets the intended mechanical and corrosion performance.

Closing Summary

Alloy 2014 remains a high-value choice in applications demanding a combination of high strength, good machinability and stable aging characteristics, particularly in aerospace and defense hardware. Its copper-driven precipitation hardening gives structural performance that outperforms many general-purpose alloys, but designers must carefully manage corrosion protection, welding procedures and heat treatment to realize optimal service life.