Aluminum A5083: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

A5083 is an aluminium–magnesium alloy in the 5xxx series, commonly referenced as AA5083. The alloy belongs to the non-heat-treatable class where solid-solution strengthening from magnesium combined with strain hardening and microalloy control dominate mechanical behavior. Major alloying additions are magnesium (the principal strengthening element, typically around 4–5 wt%), with chromium and small amounts of manganese, silicon, iron and trace elements controlling grain structure and corrosion behavior.

Key traits of A5083 include high strength among non-heat-treatable aluminium alloys, excellent resistance to marine and atmospheric corrosion, good weldability, and reasonable formability in annealed and mild-H tempers. The alloy is widely used in marine structures, pressure vessels, cryogenic tanks, railcars, and transportation components where a balance of strength, toughness and corrosion resistance is needed. Engineers select A5083 over lower-strength commercial-purity or 3xxx series alloys when improved yield/ultimate strength and enhanced seawater resistance are required without the complexity of heat-treatment processes.

A5083 is preferred over many 6xxx-series heat-treatable alloys in applications demanding superior corrosion resistance and superior performance in welded large-section components. It is selected instead of 5xxx alloys with lower Mg content when higher strength is needed, and it is chosen over stainless steels when weight savings plus good corrosion resistance provide system-level advantages. The alloy’s ability to be joined by common fusion welding processes without significant embrittlement makes it practical for large structures and field fabrication.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High (20–35%)	Excellent	Excellent	Fully annealed condition; easiest to form
H111	Medium-Low	Moderate (12–25%)	Very Good	Excellent	Partial strain-hardened, often used for sheet
H112	Medium	Moderate (10–20%)	Good	Excellent	Strain-hardened variant with reproducible properties
H32	Medium-High	Moderate (8–15%)	Good	Excellent	Strain-hardened and stabilized for moderate strength
H116	Medium-High	Moderate (8–15%)	Good	Very Good	Marine-grade temper with improved corrosion resistance
H321	Medium	Moderate (10–20%)	Good	Excellent	Stabilized by cold work and thermal treatments
H34 / H38	High	Lower (6–12%)	Fair	Good	Heavily strain-hardened tempers for maximum strength

Temper has a strong influence on both yield/ultimate strength and ductility in A5083. Annealed (O) material provides the best formability for complex forming operations and deep drawing, while H-temps progressively increase strength at the expense of elongation and bendability.

When welding or performing post-forming operations, selecting an appropriate temper acknowledges trade-offs between strength retention and ease of fabrication. Stabilized or marine tempers (H116, H321) are often specified to minimize susceptibility to exfoliation corrosion and to ensure consistent performance in aggressive environments.

Chemical Composition

Element	% Range	Notes
Si	0.40 max	Typical impurity; controlled to limit brittle intermetallics
Fe	0.40 max	Impurity element; excessive Fe can reduce ductility
Mn	0.40 max	Grain structure control and strength modifier
Mg	4.0 – 4.9	Principal strengthening element; critical for corrosion resistance
Cu	0.10 max	Kept very low to preserve corrosion resistance and weldability
Zn	0.25 max	Low; higher Zn can lower corrosion resistance
Cr	0.05 – 0.25	Microalloying for control of grain growth and resistance to sensitization
Ti	0.15 max	Grain refiner when added in controlled amounts
Others	Balance / trace	Other elements (each limited) to meet specification criteria

The relatively high magnesium content produces solid-solution strengthening and raises both yield and tensile strength relative to pure aluminium. Chromium is deliberately added in controlled amounts to stabilize the microstructure against grain growth during processing and to reduce susceptibility to exfoliation corrosion. Low copper and zinc contents are essential to preserve A5083’s superior seawater corrosion performance and to maintain weldability.

Mechanical Properties

Tensile behavior of A5083 depends strongly on temper and sheet thickness, with annealed material showing high ductility and moderate strength and H-tempers showing progressively higher yield and ultimate strength. Yield behavior in strain-hardened tempers rises significantly compared with O temper due to dislocation strengthening; however, yield point elongation and strain aging phenomena are modest because the alloy is non-heat-treatable. Elongation decreases as strength increases, and ductility must be balanced against required forming operations.

Hardness scales with work hardening and temper; HB/Brinell or Vickers readings correlate with tensile strength increases but are sensitive to thickness and heat input from welding. Fatigue performance is generally good, with endurance affected by surface finish, residual stresses from forming or welding, and exposure to corrosive environments which can accelerate crack initiation. Thickness effects are notable: thinner gauge sheet can be stronger in rolling directions due to processing, and thicker plate may display slightly lower ductility and altered toughness behavior depending on rolling and thermal history.

Mechanical property data vary with specification and thickness, but typical ranges are provided below as engineering guidance. Designers should consult mill certificates and the applicable standards for guaranteed minimum values for given tempers and thickness ranges.

Property	O/Annealed	Key Temper (e.g., H116)	Notes
Tensile Strength	200–260 MPa (29–38 ksi)	300–360 MPa (44–52 ksi)	Wide range dependent on temper and thickness; H116 shown as representative higher-strength temper
Yield Strength	55–120 MPa (8–17 ksi)	150–300 MPa (22–44 ksi)	Yield increase by strain hardening; values depend on H-number and section
Elongation	20–35%	8–18%	Ductility falls with increasing strain hardening; measured in standard tensile tests
Hardness	35–60 HB	70–110 HB	Hardness correlates to tensile strength and temper; reported as Brinell typical ranges

Physical Properties

Property	Value	Notes
Density	2.66 g/cm³	Typical for aluminium alloys; useful for mass/weight calculations
Melting Range	~605–650 °C	Solidus–liquidus interval influenced by alloying additions
Thermal Conductivity	~115–135 W/m·K	Lower than pure Al but still good for thermal management tasks
Electrical Conductivity	~29–34 %IACS	Reduced compared with pure Al due to alloying; important for electrical applications
Specific Heat	~0.90 J/g·K	Roughly equivalent to common aluminium alloys at room temperature
Thermal Expansion	~23.5–24.5 µm/m·K	Typical coefficient used in thermal stress calculations

A5083 retains many of aluminium’s favorable physical characteristics such as low density and good thermal conductivity, making it attractive where weight-critical structures require thermal management. Thermal properties are sufficiently high for heat dissipation roles but electrical conductivity is sacrificed somewhat by magnesium additions, making this alloy less desirable for high-performance electrical conductors compared with commercially pure Aluminium (1100).

Thermal expansion is similar to other aluminium alloys, and designers must account for differential expansion when joining to dissimilar materials. Melting and solidification characteristics influence welding procedures and selection of filler metals, especially for large cross-sections or heavy fabrication.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.5–6 mm	Uniform tensile behavior; affected by rolling direction	O, H111, H116, H32	Widely used for hulls, panels, and formed components
Plate	6–160 mm	Slightly lower ductility in heavy gauges; good toughness	H32, H116, H38	Used in pressure vessels, structural members and heavy fabrication
Extrusion	Cross-sections up to large sizes	Strength depends on section and extrusion ratio	H111, H32	Good for complex profiles; limited by alloy formability
Tube	Ø10 mm–large diameters	Similar strength to plate/sheet of comparable temper	O, H111, H116	Used in piping, structural tubing and fittings
Bar/Rod	Diameters and flats	Mechanical properties follow temper and cold work	H111, H114	Used for machined parts, shafts and fasteners where corrosion resistance is needed

Processing differences between sheet, plate and extruded forms influence final microstructure and mechanical anisotropy. Sheet and thin plate are typically rolled and may be supplied in controlled tempers for forming, while heavy plate often undergoes multiple thermal/mechanical cycles that affect toughness and strength. Extrusions require careful die design to avoid surface cracking and to control cooling rates which affect T4/H tempers for other alloys but mainly affect residual stresses for A5083.

Choice of product form is governed by application geometry, required mechanical properties, and fabrication pathway. Welding performance and distortion control must be considered early in design, especially for large welded assemblies and thick-section components.

Equivalent Grades

Standard	Grade	Region	Notes
AA	A5083	USA	Common designation in American Aluminium Association standards
EN AW	5083	Europe	EN designation equivalent; sometimes written as EN AW-5083
JIS	A5083	Japan	Japanese Industrial Standards use similar designation (A5083)
GB/T	5083	China	Chinese national standard equivalent; chemical and mechanical limits are harmonized but can differ in thickness ranges

Standards across regions generally align chemical limits and mechanical property guarantees, but subtle differences can arise in permitted impurity levels, temper definitions, thickness-dependent mechanical minima, and surface finish requirements. Mill certifications and the exact standard revision should be checked when substituting materials across regions to ensure compliance with local acceptance criteria and testing regimes.

Corrosion Resistance

A5083 exhibits excellent atmospheric and marine corrosion resistance due to its high magnesium content and low copper content which reduce susceptibility to localized corrosion. In seawater and splash zones, the alloy forms a stable, slow-growing oxide and hydroxide film that retards further attack, making it a preferred material for ship hulls, offshore platforms and cargo tanks. Localized pitting can occur under sustained chloride exposure if protective films are mechanically damaged or if deposits induce crevice conditions.

Stress corrosion cracking (SCC) is a recognized concern for high-magnesium alloys under tensile stress in certain environments; A5083 is generally more resistant than higher-Mg 5xxx alloys but can be susceptible if heavily cold-worked and exposed to warm chloride-containing environments. Galvanic interactions are critical in multi-material assemblies: when electrically connected to more noble materials (e.g., stainless steel, copper), A5083 will act anodically and corrode preferentially unless isolated or protected by coatings and sacrificial anodes.

Compared with 6xxx heat-treatable alloys, A5083 offers superior seawater corrosion resistance but lower maximum strength. Against 3xxx and 1xxx family alloys, A5083 trades somewhat reduced formability and conductivity for substantially higher strength and toughness in aggressive environments.

Fabrication Properties

Weldability

A5083 is considered highly weldable using common fusion processes including TIG (GTAW) and MIG (GMAW), and it is often welded in the field for shipbuilding and structural applications. Recommended filler alloys include ER5183 and ER5356, chosen to balance strength, corrosion resistance and ductility in the weld metal; ER5183 is frequently selected where corrosion resistance and toughness are prioritized. Hot cracking risk in A5083 is low, but the heat-affected zone (HAZ) near welds can experience some softening in heavily strain-hardened tempers; proper weld procedure qualification and control of interpass temperature are important to minimize distortion and property loss.

Machinability

Machining of A5083 is considered fair to poor relative to free-machining aluminium alloys; the high ductility and gummy chips demand careful tooling choices and cutting parameters. Carbide tooling with polished flutes, positive shear geometry, and effective chip control strategies are recommended to avoid built-up edge and tool rubbing. Moderate cutting speeds, relatively high feed rates, and flood lubrication help manage heat and produce acceptable surface finish; machinability indices for A5083 typically place it below 6xxx and most 2xxx alloys but better than many high-strength Al–Mg–Si-free alloys.

Formability

Formability is excellent in the annealed O temper and remains good in lightly hardened H tempers, but sharp bends and deep draws will require O or mild H tempers for lower scrap risk. Minimum bend radii depend on temper, thickness and geometry; as a guideline, 90° bends in O temper can often be formed with inner radii close to 1–2× thickness, whereas H32/H116 tempers may require 2–4× thickness to avoid cracking. Cold working increases strength via strain hardening, and intermediate anneals are applied when severe forming sequences are required to restore ductility.

Heat Treatment Behavior

A5083 is a non-heat-treatable alloy and does not respond to conventional solution-and-age treatments used for 2xxx and 6xxx series alloys. Strength modulation is achieved almost entirely through cold work (strain hardening) and tempering designations (H tempers) which define the degree of mechanical deformation and/or natural aging stabilization.

Annealing is used to soften and restore ductility; typical annealing for substantial softening is carried out in the 300–415 °C range with controlled cooling to achieve the O temper. Stabilization and stress-relief procedures may be applied after forming or welding to set temper and reduce distortion, though such thermal cycles will also alter strength and must be planned to avoid unintended property loss. Because the alloy cannot be precipitation-hardened, performance improvements rely on mechanical processing sequences and control of impurity elements.

High-Temperature Performance

At elevated temperatures, A5083 experiences progressive loss of yield and tensile strength, with notable degradation beginning above 100 °C under static loading. For sustained structural service, designers commonly limit continuous use to temperatures below approximately 100–120 °C; intermittent exposure may be tolerated at higher temperatures but risks accelerated environmental degradation and loss of mechanical integrity. Oxidation is not severe compared with steels, but prolonged high-temperature exposure in oxidizing atmospheres and thermal cycling can alter surface films and promote localized corrosion.

Weld heat-affected zones can behave as local high-temperature exposures and may produce softened bands, reduced strength and potential susceptibility to stress corrosion cracking if residual tensile stresses and corrosive environments are present. For high-temperature or cryogenic service, property data specific to the design temperature and thickness must be examined; A5083 maintains good toughness at low temperatures, which is why it’s used for cryogenic tanks in certain configurations.

Applications

Industry	Example Component	Why A5083 Is Used
Marine	Ship hulls, superstructures, bulkheads	Excellent seawater corrosion resistance and good strength-to-weight
Automotive / Transportation	Trailer beds, tankers, railcar panels	High-strength, weldable, and good fatigue resistance for structural panels
Aerospace / Defense	Structural fittings, flooring, brackets	Combination of light weight, toughness and corrosion performance
Pressure Vessels	Cryogenic tanks, LPG containers	Good toughness at low temperatures and weldability for large tanks
Electronics / Thermal Management	Moderate-duty heat spreaders	Adequate thermal conductivity with lightweight structure

A5083’s combination of corrosion resistance, weldability and non-brittle fracture behavior keeps it a material of choice across marine, transport and select pressure vessel applications. Designers commonly exploit its high Mg-driven strength in welded assemblies where post-weld heat treatments are impractical.

Selection Insights

When selecting A5083, prioritize it for applications where seawater or aggressive atmospheric corrosion resistance is required together with good weldability and moderate-to-high strength. Choose annealed (O) tempers for extensive forming and H- tempers (H116/H32/H111) when you need higher as-fabricated strength and stability in corrosive service. Consider thickness and weld effects early, since HAZ softening and thickness-dependent property limits can influence allowable design stresses.

Compared with commercially pure aluminium (e.g., 1100), A5083 sacrifices electrical conductivity and ultimate formability for substantially higher yield and tensile strength, making it preferable where structural performance is needed. Against 3xxx/5052-class work-hardened alloys, A5083 typically provides superior strength and comparable or better corrosion resistance, at modest additional material cost. Versus heat-treatable alloys like 6061, A5083 gives better marine corrosion resistance and weldability but lower peak strength; opt for A5083 over 6xxx alloys when corrosion resistance and welded structural robustness outweigh the need for maximum strength.

Closing Summary

A5083 remains a widely used engineering aluminium due to its practical combination of solid-solution strengthening, excellent seawater corrosion resistance, and reliable weldability across multiple product forms. Its suitability for welded structures, pressure vessels and marine applications ensures continued relevance where a balance of strength, toughness and corrosion resistance is required without reliance on heat-treatment cycles.