Aluminum 5457: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

5457 is an alloy in the 5xxx series of aluminum alloys, placing it in the Al–Mg family where magnesium is the principal alloying addition. As a member of the 5xxx family it is non-heat-treatable; strengthening is achieved primarily through Mg in solid solution and by strain hardening during forming operations.

Major alloying elements in 5457 are magnesium at relatively high levels (typically around 4–5 wt%) with controlled additions of manganese and trace amounts of chromium and titanium to refine grain structure and control recrystallization. These alloying choices yield a combination of elevated strength for a wrought aluminum sheet and improved resistance to general corrosion compared with many 1xxx–3xxx series alloys.

Key traits of 5457 include moderate-to-high strength for a non-heat-treatable alloy, good weldability with appropriate filler metals, reasonable formability in softer tempers, and good resistance to atmospheric and marine corrosion when properly finished. Typical industries using 5457 are automotive exterior bodywork and closures, transportation trailers and panels, general structural components, and some marine and architectural applications where a favorable strength-to-weight and corrosion resistance combination is required.

Engineers choose 5457 over other alloys when a balance of higher yield and tensile strength than common work-hardened alloys (3000/5000-series lower-Mg grades) is required without resorting to heat-treatable 6xxx or 7xxx alloys that complicate forming and welding. It is selected when higher Mg-driven strength is needed while maintaining superior corrosion resistance and good paintability for exterior applications.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High	Excellent	Excellent	Fully annealed, maximum ductility for forming
H111	Medium-High	Moderate	Good	Very good	One-direction strain-hardened, common for sheet forming
H14	Medium	Moderate-High	Very good	Very good	Quarter-hard temper for moderate forming with higher strength
H18	High	Low	Limited	Good	Full-hard for applications needing maximum as-rolled strength
H32	Medium-High	Moderate	Good	Very good	Strain-hardened and stabilized; used to limit springback
H116 / H321	Medium-High	Moderate	Good	Very good	Stabilized tempers for improved resistance to stress corrosion and paint bake cycles

Tempering in 5457 is used to balance manufacturability and as-fabricated strength; softer tempers (O, H14) are used for deep drawing and complex forming while harder tempers (H18, H32) offer larger as-produced yield and tensile values. Stabilized variants such as H116 or H321 are selected for marine or painted applications because they limit precipitation changes during thermal exposure and reduce susceptibility to stress-corrosion phenomena.

Because 5457 is non-heat-treatable, changes in mechanical properties are dominated by cold work, strain aging, and thermal stabilization rather than solution and aging treatments common to the 6xxx or 7xxx families.

Chemical Composition

Element	% Range	Notes
Si	≤ 0.25	Typical impurity; kept low to preserve ductility and corrosion resistance
Fe	≤ 0.40	Impurity that can form intermetallics affecting toughness and surface finish
Mn	0.20–0.80	Controls grain structure and improves strength and toughness
Mg	4.0–5.0	Principal strengthening element providing solid-solution strengthening
Cu	≤ 0.10	Kept low to retain corrosion resistance; higher Cu increases strength but reduces corrosion resistance
Zn	≤ 0.25	Minor; higher levels could promote galvanic activity
Cr	0.05–0.25	Added to control recrystallization and improve resistance to grain boundary corrosion
Ti	≤ 0.15	Grain refiner added in small amounts during casting/ingot preparation
Others (each)	≤ 0.05–0.15	Includes trace elements; balance is Al

The high magnesium content is the primary driver of 5457’s elevated strength relative to lower-Mg 5xxx alloys. Manganese refines grain size and augments strength without significant loss of corrosion resistance. Small amounts of chromium and titanium are deliberate microalloying additions to stabilize the structure and control grain growth during thermomechanical processing, which helps preserve formability and limit recrystallization-related softening.

Mechanical Properties

Tensile behavior of 5457 depends strongly on temper and sheet thickness: softer tempers deliver high elongation and lower yield, while strain-hardened tempers move yield and ultimate tensile strength upward with reduced elongation. Yield points in work-hardened tempers are relatively high for a non-heat-treatable alloy, delivering useful design margins in thin-gauge structural panels.

Hardness tracks the tensile strength and increases with cold work; H18-type conditions achieve the highest Brinell or Vickers values available for this alloy, while O-condition tests report much lower hardness consistent with excellent formability. Fatigue performance is generally good for transportation applications provided surface finish and corrosion protection are controlled; fatigue life is sensitive to welding, notches, and surface scratches.

Thickness effects are significant: thinner gauges typically achieve higher apparent yield and tensile values after rolling and cold working due to increased work hardening, whereas thick plate or extrusion stock will often be softer and exhibit lower elongation. Design engineers must therefore use properties tied to the alloy temper and specific product form and thickness rather than a single blanket value.

Property	O/Annealed	Key Temper (H111/H32 typical)	Notes
Tensile Strength (MPa)	200–260	320–380	Values vary with thickness and degree of strain hardening; quoted ranges are typical for sheet products
Yield Strength (MPa)	80–150	200–310	Yield rises sharply with cold work; specification must reference temper and thickness
Elongation (%)	18–30	8–18	Ductility declines as strength increases; formability should be assessed in required temper
Hardness (HB)	35–60	80–110	Hardness correlates to tensile strength and cold work level; hardness testing useful for QA

Physical Properties

Property	Value	Notes
Density	~2.69 g/cm³	Slightly lower than some other high-alloy Al products; good strength-to-weight ratio
Solidus/Liquidus	~605–650 °C	Alloying broadens the melting interval compared with pure Al
Thermal Conductivity	~120–140 W/m·K (25 °C)	Lower than pure Al; acceptable for general thermal management but less than pure 1xxx alloys
Electrical Conductivity	~28–36 % IACS	Reduced by Mg and Mn additions; important for electrical applications and joining considerations
Specific Heat	~880–920 J/kg·K	Typical for aluminum alloys near ambient temperature
Coefficient of Thermal Expansion	~23–24 µm/m·K	Typical for Al alloys; consider differential expansion with steels or composites

The alloy’s physical properties make 5457 attractive where low mass and reasonable thermal performance are needed, but it is not chosen when maximal thermal or electrical conductivity is required. The thermal expansion is typical for Al and must be taken into account in assemblies combining dissimilar materials to avoid stress buildup during temperature cycles.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.5–4.0 mm	Strength increases with cold reduction and strain-hardening	O, H14, H111, H32	Most common form used in automotive panels and architectural cladding
Plate	>4.0 mm	Lower work hardening compared with thin sheet; machined or welded structural uses	O, H112	Used where stiffness, weldability and drilling are required
Extrusion	Sectional profiles	Strength depends on extrusion ratio and subsequent cold work	O, H22, H32	Used for structural frames and stiffeners where lightweight strength is needed
Tube	Ø small to large	Strength governed by wall thickness and temper	H14, H32	Used in lightweight structures, railings, and transport frames
Bar/Rod	Various diameters	Typically softer unless cold-drawn	O, H12	Used for fasteners, machined fittings and fabricated parts

Processing differences influence the mechanical response and the intended applications: sheet is frequently cold-rolled and strain-hardened for body panels, while extrusions and plate are often supplied in softer tempers to allow later forming or machining. Welding and joining strategies also differ by form; for example, tube and extrusion welding usually require filler metals and pre- or post-weld treatments to manage HAZ softening.

Equivalent Grades

Standard	Grade	Region	Notes
AA	5457	USA	Designation used in North American standards and supplier catalogs
EN AW	5457	Europe	EN designation aligns numerically with AA; chemical and mechanical limits may vary slightly by standard
JIS	—	Japan	No exact one-to-one JIS grade; similar properties to high-Mg Al–Mg series products but check local spec
GB/T	5457	China	Chinese standards may list 5457 with comparable composition but specify different tolerances and tempers

There is often a close numerical match (EN AW-5457) in European specifications, but minor permitted differences in impurity limits, temper designations, and testing protocols mean engineers should compare certificates of analysis rather than assume interchangeability. For JIS and some national standards there may be no exact counterpart; in such cases selection is done based on matching composition and mechanical property envelopes rather than a single grade label.

Corrosion Resistance

5457 demonstrates good general atmospheric and industrial corrosion resistance owing to the protective aluminum oxide layer and the relatively clean alloy chemistry. The substantial magnesium content increases overall corrosion resistance compared with many 1xxx and 3xxx alloys but can raise sensitivity to certain localized corrosion modes if impurities (Fe, Si) are elevated. Proper surface finishes, coatings, and anodizing enhance long-term durability in exposed architectural and transportation applications.

In marine environments 5457 performs well for many structural applications, but susceptibility to stress-corrosion cracking (SCC) increases as magnesium content and tensile stress levels rise. Stabilized tempers (H116/H321) or post-weld treatments are commonly used to mitigate SCC risk for service in chloride-containing atmospheres. Galvanic interactions with more noble metals (e.g., copper, stainless steels) require attention; appropriate isolation and fastener selection prevent accelerated localized attack.

Compared with 6xxx heat-treatable alloys, 5457 is generally superior for long-term corrosion resistance in many chloride environments, while 6xxx alloys may exhibit higher peak strength but lower intrinsic corrosion resistance without protective measures. Relative to low-Mg 3xxx or pure 1xxx alloys, 5457 gives better strength without a severe penalty to corrosion resistance, making it suitable for exterior structural panels and marine superstructures.

Fabrication Properties

Weldability

5457 is readily welded by common fusion processes (TIG, MIG/GMAW) and performs well with appropriate aluminum-magnesium filler alloys such as ER5356 and ER5183, which provide good ductility and corrosion resistance in the weld metal. Hot-cracking risk is relatively low compared with some high-copper alloys, but careful joint design and control of weld heat input are necessary to minimize HAZ softening and distortion. Post-weld mechanical properties in the HAZ will be reduced relative to the cold-worked parent metal, so joint design and possible post-weld mechanical treatments must be considered in high-stress applications.

Machinability

Machinability of 5457 is moderate compared with free-cutting steels or the 6xxx alloys; the alloy can gall if cutting parameters are not optimized. Carbide tooling with appropriate positive rake angles, rigid workholding, and flood coolant is recommended for milling and turning of plate and extruded sections. Use moderate cutting speeds and higher feed rates to break chips; interrupted cuts benefit from tougher grades of carbide or coatings to resist edge chipping.

Formability

Forming performance depends on temper and gauge: fully annealed (O) and mild work-hardened tempers permit deep drawing and complex stamping; stronger tempers reduce allowable bend radii and increase springback. Typical bend radii for sheet gauge applications are on the order of 2–4× thickness in softer tempers, increasing for harder tempers; always verify with forming trials for complex geometries. Warm forming and careful tool design can extend formability for higher-strength tempers while minimizing splitting and edge cracking.

Heat Treatment Behavior

As a member of the non-heat-treatable 5xxx family, 5457 does not respond to solution and artificial aging to develop higher strength. The principal mechanisms available are cold work and thermal stabilization. Solution treatment and quench/age cycles applied to 5457 will not produce the kind of precipitation hardening observed in 6xxx alloys; therefore, designers rely on rolling and strain hardening to set in-service properties.

Annealing (O temper) removes prior cold work and restores ductility for forming operations; subsequent controlled cold working produces balance of strength and elongation for service. Stabilized tempers (e.g., H116, H321) are achieved by low-temperature thermal exposures or controlled aging to reduce susceptibility to strain aging and stress-corrosion cracking without significantly lowering strength.

High-Temperature Performance

5457 maintains usable strength at moderately elevated temperatures but experiences progressive loss of yield and tensile strength as temperature increases above ~100 °C. For continuous service beyond 100–150 °C designers should validate mechanical property retention since prolonged exposure can cause recovery and partial annealing of cold-worked microstructures. Oxidation rate is modest and typical of aluminum alloys; protective coatings and anodizing enhance high-temperature surface stability.

Weld heat-affected zones can show localized softening that is exacerbated by elevated service temperatures, so attention to joint design and heat management is critical when assemblies will experience both welding and thermal cycling. Thermal expansion and differential stiffness relative to adjoining materials must be checked for high-temperature applications to prevent fatigue or stress concentrations.

Applications

Industry	Example Component	Why 5457 Is Used
Automotive	Exterior body panels, inner reinforcement panels	Offers higher strength than common work-hardened alloys while retaining good formability and paintability
Marine	Superstructure panels, deck fittings	Good corrosion resistance in marine atmospheres and reasonable weldability for fabrications
Aerospace / UAV	Secondary structural fittings, fairings	Favorable strength-to-weight for non-primary structural parts and good surface finish for aerodynamic skins
Transportation	Trailer panels, container walls	Combination of stiffness, toughness and corrosion resistance for exposed structural skins
Electronics / Thermal management	Lightweight brackets, mechanical supports	Adequate thermal conductivity and low density for lightweight supports; not primary choice for high-performance heat sinks

5457 is commonly chosen where mid-to-high strength, good corrosion resistance and fabrication versatility are required without the complexity of heat treatments. It is particularly well-suited to automotive outer panels and transport skins where repeated forming and welding operations are part of production.

Selection Insights

When selecting 5457, prioritize applications that demand higher yield and tensile strength than commercially pure aluminum (e.g., 1100) while still needing good corrosion resistance and formability. Compared with 1100, 5457 sacrifices electrical and thermal conductivity and ultimate ductility in exchange for markedly higher structural strength.

Against common work-hardened alloys such as 3003 or 5052, 5457 sits higher on the strength scale while retaining comparable or better resistance to general corrosion; choose 5457 when additional strength is justified despite potential increased cost and slightly reduced formability. Compared with heat-treatable alloys like 6061 or 6063, 5457 will not reach the peak strength of those alloys after aging but often offers superior weldability and corrosion resistance without heat-treatment complexity, so prefer 5457 where fabrication simplicity and corrosion performance outweigh the need for the absolute highest strength.

• Use 5457 for exterior structural skins, welded assemblies and where stress-corrosion risk is manageable with stabilized tempers.
• Avoid specifying 5457 if maximum electrical conductivity, extreme formability for complex deep drawing, or peak heat-treated strength is the primary requirement.

Closing Summary

5457 remains a relevant engineering alloy where a robust combination of Mg-driven strength, corrosion resistance and fabrication versatility is required without heat treatment complexity. Its balance of mechanical and corrosion properties makes it a pragmatic choice for automotive, marine and transportation applications that demand lightweight, weldable and formable structural materials.