Aluminum 5080: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

Alloy 5080 is a member of the 5xxx series aluminum-magnesium family, categorized as a non-heat-treatable (work-hardenable) alloy. Its primary strengthening mechanism is solid-solution strengthening from magnesium combined with strain hardening through cold work.

Typical major alloying elements are magnesium at several weight percent with low additions of manganese and chromium to control grain structure and recrystallization. This chemistry gives 5080 a balance of medium-to-high strength, good ductility in annealed tempers, excellent seawater corrosion resistance, and generally favorable weldability.

Key traits include a favorable strength-to-weight ratio compared with common pure aluminum grades, resistance to pitting and crevice corrosion in marine environments, and reasonable formability in soft tempers. Industries that commonly use 5xxx series alloys such as 5080 include shipbuilding and marine structures, pressure vessels, structural components, and fabricated equipment where corrosion resistance and moderate strength are required.

Engineers select 5080 when a combination of higher as-delivered strength than 1xxx alloys, superior marine corrosion resistance versus many heat-treatable alloys, and good weldability are required. It is typically chosen over lower-strength 1xxx or 3xxx series alloys when stiffness and yield are important and over 6xxx/7xxx alloys when corrosion resistance and weld repairability are priorities.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High	Excellent	Excellent	Fully annealed condition; best formability and corrosion resistance
H111 / H112	Low-Moderate	High-Moderate	Good	Excellent	Slight work hardening from forming or processing
H14	Moderate	Moderate	Fair	Excellent	One quarter hard; used for moderate forming with higher strength
H18	High	Low	Poor	Excellent	Full hard; used for stiffening and low-deformation parts
H116 / H321	Moderate-High	Moderate	Fair	Good	Commercial tempers with controlled stress relief for welded structures
T5 (if artificially aged)	Moderate-High	Moderate	Fair	Good	Some applications see T5-like treatments for dimensional stability
T6 / T651 (rare)	Moderate-High	Moderate	Fair	Good	Uncommon and limited benefit because alloy is not primarily heat-treatable

Tempering for 5080 is predominantly achieved by cold-work (H-temper) and stress-relief rather than classical solution-and-age treatments. Annealed (O) material offers the best stretch formability and highest elongation, while increasing H-numbers trade ductility for yield and strength.

Welded structures are commonly delivered in H116/H321 variants when relaxation control is needed; H-tempers retain good weldability but will show HAZ softening adjacent to welds that must be considered in design.

Chemical Composition

Element	% Range	Notes
Si	0.40 max	Impurity; lowered to maintain ductility and corrosion resistance
Fe	0.40 max	Intermetallic former; controlled to limit fracture initiation
Mn	0.30–1.0	Provides grain refinement and improves strength and toughness
Mg	3.8–4.9	Principal strengthening element; critical for corrosion behavior
Cu	0.10 max	Kept low to preserve corrosion resistance and weldability
Zn	0.25 max	Low to avoid reducing corrosion resistance
Cr	0.05–0.25	Controls grain structure and reduces recrystallization/sensitization
Ti	0.05 max	Grain refiner in cast or wrought processing
Others (including Zr)	Balance/trace	Minor elements used for microstructure control; total others typically <0.15%

The alloy’s performance is dominated by magnesium, which supplies the majority of the solid-solution strengthening and contributes to marine corrosion resistance. Manganese and chromium are deliberate microalloying additions used to control grain size, limit recrystallization, and reduce susceptibility to intergranular corrosion during thermal cycles. Low levels of copper and zinc are maintained to avoid compromising corrosion resistance and weldability while silicon and iron are kept low as unavoidable impurities.

Mechanical Properties

5080 shows classical work-hardenable tensile behavior: annealed sheet exhibits high elongation with relatively low yield strength, and progressive cold work increases yield and ultimate strengths while reducing ductility. Yield strength and tensile strength depend strongly on temper and thickness, with H-temper products providing a substantial increase in 0.2% offset yield at the expense of elongation. Hardness follows the same trend and correlates with both magnesium content and cold-work level rather than age-hardening.

Fatigue performance is moderate for the 5xxx family; surface condition, welded joints, and residual stresses dominate fatigue life. Thicker sections of 5080 tend to have slightly lower measured strength because of mill annealing, grain size changes, and residual stress profiles; designers should apply thickness-dependent properties from supplier mill certificates for critical components. Impact toughness at ambient temperatures is generally good, but performance declines when the alloy is severely cold worked or heavily welded without post-weld stress relief.

In corrosive or welded structures, designers must account for HAZ softening that locally reduces yield and tensile strength; mechanical design should treat welded joints as potential low-strength zones and incorporate appropriate safety factors or reinforcement. For pressure or structural applications, standard engineering practice calls for using supplier-certified mechanical-property data tied to specific thickness and temper.

Property	O/Annealed	Key Temper (e.g., H116/H18)	Notes
Tensile Strength	220–300 MPa (typical range)	260–350 MPa (depending on cold work)	Ultimate tensile varies with temper and thickness
Yield Strength (0.2% offset)	90–180 MPa	200–320 MPa	Yield increases strongly with cold work; H18 at high end
Elongation	20–30%	6–18%	Annealed condition yields highest elongation
Hardness (HB)	40–60 HB	60–95 HB	Brinell correlated to temper and Mg content

Physical Properties

Property	Value	Notes
Density	2.66 g/cm³	Typical for Al-Mg alloys; used for mass calculations
Melting Range	570–645 °C	Solidus–liquidus range depends slightly on alloying content
Thermal Conductivity	≈130 W/m·K	Reduced from pure Al due to alloying; still good for heat dissipation
Electrical Conductivity	~30–40 % IACS	Lower than pure Al; conductivity drops with increasing Mg and cold work
Specific Heat	≈0.90 kJ/kg·K	Typical for aluminum alloys at room temperature
Thermal Expansion	≈23.5 µm/m·K	Linear expansion similar to other Al alloys; design accordingly

The physical property set places 5080 among moderately conductive aluminum alloys; thermal conductivity is adequate for many heat-sinking or dissipative applications but is inferior to pure Al and certain 1xxx series alloys. Density and thermal expansion values support lightweight structural design but require attention when joining to dissimilar materials with different expansion coefficients.

Electrical conductivity is degraded relative to pure aluminum and declines further with cold work and heavy alloying. Where electrical conduction is critical, 5080 is less favorable than low-alloyed or pure aluminum grades.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.5–6.0 mm	Uniform, thickness-dependent strength	O, H111, H116, H18	Common for hull plating, panels, and fabricated assemblies
Plate	6–150 mm	Slightly lower reported strengths at larger thickness	O, H116, H321	Used for structural members and pressure-bearing components
Extrusion	Sections up to 300 mm	Strength depends on section profile and cold work	O, H111, H14	Tubes, profiles used where welded assemblies are required
Tube	1.0–25 mm wall	Similar to sheet/plate; welding and cold work affect properties	O, H112, H321	Pressure and fluid handling where corrosion resistance is needed
Bar/Rod	Diameters up to 200 mm	Typically supplied annealed or quarter/hard	O, H14, H18	Machined components and forged blanks

Processing routes differ by product form: sheet and plate are commonly rolled and annealed with controlled mill finishes, while extrusions require careful control of billet chemistry and quench to maintain homogenized microstructure. Plate and heavy sections will often be delivered with stress-relief tempers to minimize distortion during welding and fabrication.

Designers must consider that forming and fabrication operations change local temper and residual stress; re-annealing or controlled pre-strain may be required for complex assemblies to achieve desired mechanical performance.

Equivalent Grades

Standard	Grade	Region	Notes
AA	5080	USA	Primary designation in Aluminum Association listings
EN AW	5080	Europe	Follows EN standards; chemical limits similar to AA designation
JIS	A5080 (where used)	Japan	JIS variants may have slightly different impurity limits
GB/T	5080 (or equivalent EN designation)	China	Chinese standard commonly aligns with AA/EN chemical ranges

Although the AA, EN, JIS, and GB/T designations for 5080 are nominally equivalent, subtle differences exist in allowable impurity limits, required testing (UL/UT/NDT), and permitted mechanical-property ranges for specific product forms and tempers. Sourcing across regions requires careful cross-referencing of mill certificates to confirm exact composition, temper designation, and acceptance criteria for critical applications. Material standards may also prescribe different rolling or heat-treatment histories that influence delivered microstructure and performance.

Corrosion Resistance

5080 delivers robust atmospheric and marine corrosion resistance owed to its significant magnesium content and low copper content. The alloy forms a stable protective oxide film and resists pitting and crevice corrosion in seawater better than many heat-treatable series; this makes it a favored choice for hulls, decks, and offshore equipment.

However, alloys in the 5xxx family with magnesium contents above about 3% can be susceptible to sensitization and subsequent intergranular corrosion when exposed to elevated temperatures (typically encountered during welding) unless chromium or other stabilizers are present at effective levels. Proper filler selection, welding procedures, and post-weld treatments are therefore important to limit long-term degradation.

Galvanic interactions should be expected when 5080 is coupled with more noble metals (stainless steels, copper alloys); isolating materials or protective coatings are advisable to prevent accelerated local corrosion. Compared with 6xxx and 7xxx series alloys, 5080 is superior in natural seawater environments but offers lower peak strength than some heat-treatable alloys that may require additional corrosion protection.

Fabrication Properties

Weldability

5080 welds well with TIG (GTAW) and MIG (GMAW) processes; typical filler alloys recommended are 5183 (Al-Mg) and 5356 to match magnesium content and preserve corrosion resistance. Hot-cracking risk is low compared to high-copper alloys, but special attention is required for HAZ softening and potential sensitization in sections with higher Mg. Pre-weld cleaning to remove contaminants and controlled heat input to limit time at sensitization temperatures are best practices.

Machinability

Machining of 5080 is moderate; it is not as free-cutting as some 6xxx and 2xxx alloys. Carbide tooling is recommended, with moderate cutting speeds and higher feed rates to avoid built-up edge. Surface finish and chip control are influenced by temper and microstructure; heavy cold-worked tempers increase tool forces and reduce machinability. Coolant and chip-breaker strategies are important for sustained tool life.

Formability

Formability is excellent in O tempers, allowing deep drawing, stretching, and complex bends with small punch radii. Minimum bend radii depend on temper and thickness but commonly range from 1.0–2.5 × material thickness for many sheet applications; H-tempers demand larger radii. Because forming increases yield through strain hardening, progressive forming schedules and intermediate anneals are used for severe deformation to prevent cracking.

Heat Treatment Behavior

As a non-heat-treatable alloy, 5080 does not respond to solution treatment and age-hardening in the same way as 6xxx or 7xxx series alloys. Instead, its mechanical properties are controlled by cold work (rolling, drawing, bending) and by thermal stabilization treatments such as stress-relief anneals.

Full annealing (O temper) is performed at elevated temperatures to restore ductility and reduce residual stresses; subsequent cold working increases yield and tensile strengths. Attempts at artificial aging or solution treatment will not yield the type of precipitation strengthening seen in heat-treatable aluminum alloys, so thermal cycles are used primarily to control recrystallization and corrosion sensitivity rather than to create peak-strength microstructures.

High-Temperature Performance

Operational strength of 5080 degrades with temperature; useful structural service is typically limited to temperatures below about 100–150 °C for load-bearing applications. Above this range, significant softening occurs, and time-at-temperature accelerates microstructural changes that reduce load-carrying capacity.

Oxidation at elevated temperature is not severe compared with ferrous metals, but prolonged exposure can lead to surface scaling and altered corrosion behavior. In welded zones, exposure to elevated temperatures can exacerbate HAZ softening and sensitization; designers should avoid thermal cycles that exceed recommended limits or apply post-heat treatments when necessary.

Applications

Industry	Example Component	Why 5080 Is Used
Marine	Hull panels, superstructures	Excellent seawater corrosion resistance and reasonable strength
Automotive	Trailer beds, cargo panels	Good strength-to-weight and formability for stamped parts
Aerospace	Non-critical fittings, fairings	Corrosion resistance with favorable density for secondary structures
Pressure Vessel / Storage	Tanks and pressure parts	Good weldability and resistance to many aqueous environments
Electronics / Thermal	Chassis and moderate heat sinks	Balance of thermal conductivity and structural properties

5080 is commonly specified where corrosion resistance and weldability drive material selection while moderate strength and good formability are required. Its combination of properties makes it an economical choice for structural, marine, and general fabrication applications where peak-age hardened strength is not the primary requirement.

Selection Insights

Choose 5080 when you need a 5xxx-series balance of moderate-to-high strength, excellent marine corrosion resistance, and good weldability. It is particularly appropriate for welded structures and components exposed to seawater or industrial atmospheres where post-fabrication protection should be minimal.

Compared with commercially pure aluminum (1100), 5080 sacrifices some electrical and thermal conductivity and slightly reduced formability in return for substantially higher yield and tensile strength. Compared with work-hardened alloys such as 3003 or 5052, 5080 offers higher strength and often superior seawater performance but may be less formable in harder tempers. Compared with heat-treatable alloys like 6061/6063, 5080 provides better natural corrosion resistance and weldability at the cost of lower peak aged strength; choose 5080 when corrosion resistance and weld repairability outweigh the need for maximum static strength.

Closing Summary

Alloy 5080 remains a practical engineering alloy for applications demanding a combination of corrosion resistance, weldability, and moderate structural strength. Its work-hardenable nature, controlled chemistry, and availability in multiple product forms make it a versatile choice for marine, structural, and general fabrication uses where durability in aggressive environments is a priority.