Magnesium Alloy AZ81A
ASTM AZ81A · UNS M11810
AZ81A is a sand and permanent-mould Mg-8Al-1Zn casting alloy (UNS M11810) normally supplied solution treated (T4), where about 83 MPa yield, 275 MPa tensile and 15% elongation give the highest ductility of the Mg-Al-Zn casting family.
Reference datasheet — AZ81A is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the T4 condition
AZ81A tempers and conditions
AZ81A is supplied in 2 conditions, soft to hard. T4 is the default FabDigit quotes; the values on this page are for it.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
T4Default Solution heat treated and naturally aged | The standard supply condition for AZ81A — best combination of tensile strength, elongation and impact toughness for pressure-tight aerospace sand castings. | 83 | 275 | 15 | 55 HB | 11.3 % IACS |
As fabricated | Pick only for non-critical castings or when the part is to be heat treated later; ductility is low because of the coarse Mg17Al12 network. | 85 | 160 | 3 | 60 HB | 12.2 % IACS |
What is AZ81A?
AZ81A is a sand and permanent-mould Mg-8Al-1Zn casting alloy (UNS M11810) normally supplied solution treated (T4), where about 83 MPa yield, 275 MPa tensile and 15% elongation give the highest ductility of the Mg-Al-Zn casting family. It was developed for pressure-tight aerospace housings because good fluidity and low microporosity survive leak testing; thermal conductivity is 51 W/m·K and electrical conductivity 11.3% IACS. Bare corrosion resistance is low (18), service is limited to about 120 °C, and weldability is moderate (62). AZ91 is the usual alternative when higher yield strength matters more than elongation. AZ81A has a density of 1.8 g/cm³ (0.065 lb/in³), lighter than 63% of magnesium alloy grades. It melts at 490°C (914 °F). AZ81A has a yield strength of 83 MPa (12 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 99% of magnesium alloy grades. Elongation at break is 15% and the elastic modulus is 45 GPa (6.53 Msi).
What is AZ81A used for?
- Pressure-tight housings
- Aerospace sand castings
- Gearbox and accessory-drive cases
- Hydraulic and pneumatic valve bodies
- Instrument and avionics enclosures
- Permanent-mould covers and manifolds
Advantages
- Ductile — tolerates forming and impact — 15%, better than 87% of magnesium alloy grades
Limitations
- Low strength — 83 MPa (12 ksi), worse than 99% of magnesium alloy grades
- Poor heat conductor — 51 W/m·K (29.5 BTU/hr·ft·°F), worse than 97% of magnesium alloy grades
- Low electrical conductivity — 11.3 % IACS, worse than 96% of magnesium alloy grades
- Hard to polish — 45/100, worse than 93% of magnesium alloy grades
- Limited service temperature — 120°C (248 °F), worse than 78% of magnesium alloy grades
AZ81A properties
Typical room-temperature values for AZ81A-T4; bars are the position among magnesium alloy grades.
Physical3
AZ81A has a density of 1.8 g/cm³ (0.065 lb/in³), lighter than 63% of magnesium alloy grades. It melts at 490°C (914 °F).
Mechanical13
AZ81A has a yield strength of 83 MPa (12 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 99% of magnesium alloy grades. Elongation at break is 15% and the elastic modulus is 45 GPa (6.53 Msi).
Thermal6
AZ81A is rated for continuous service to 120°C (248 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), worse than 97% of magnesium alloy grades. Thermal expansion is 26 µm/m·K (14.4 µin/in·°F).
Electrical3
AZ81A conducts electricity at 11.3 % IACS, worse than 96% of magnesium alloy grades.
Chemical & Environmental3
Corrosion resistance is poor (18/100), worse than 88% of magnesium alloy grades.
Sustainability4
Producing a kilogram of AZ81A takes about 350 MJ of energy and emits 30 kg of CO₂ — more than 74% of magnesium alloy grades. Typical recycled content is 30%.
Manufacturability8
AZ81A's machinability is excellent (95/100, better than 54% of magnesium alloy grades); weldability good (62/100); formability poor (15/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the magnesium alloy family
Yield strength against density for every magnesium alloy grade FabDigit runs. AZ81A is highlighted; hover a dot for its name, or open the interactive family chart.
Working with AZ81A
Is AZ81A easy to machine?
Outstanding machinability — very high speeds, low cutting forces, sharp positive-rake tools, no coolant containing water where possible, and strict chip/fines fire control (never water-quench a Mg fire).
Can AZ81A be welded?
GTAW/GMAW weldable with AZ92A or AZ101A filler; preheat 250–300 °C for heavy sections, then re-solution treat (T4) to restore ductility and relieve stress in the HAZ.
Can AZ81A be formed, bent or molded?
Sand and permanent-mold casting alloy with good fluidity and pressure tightness; needs melt protection (SF6-free cover gas), grain refinement by superheat, and generous fillets to avoid hot tearing — no cold forming.
AZ81A chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Al | 7 – 8.1 | 7.6 |
| Zn | 0.4 – 1 | 0.7 |
| Mn0.13 % min required for corrosion control | 0.13 – 0.35 | 0.2 |
| Si | ≤ 0.3 | |
| Cu | ≤ 0.1 | |
| Ni | ≤ 0.01 | |
| Fehigh-purity limit | ≤ 0.01 | |
| Others (each)0.30 % max total | ≤ 0.1 | |
| Mg | balance |
What surface finishes work on AZ81A?
Always apply a chromate-free conversion coat or Mg anodic/PEO coating (Dow 17, HAE) plus epoxy primer/topcoat; isolate from steel and aluminium fasteners to prevent galvanic attack.
Equivalent designations
Standards and trade names that resolve to Magnesium Alloy AZ81A in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- M11810
How much does AZ81A cost?
AZ81A is a premium-cost magnesium alloy ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
AZ81A — frequently asked
What is AZ81A used for?
AZ81A is typically used for pressure-tight housings, aerospace sand castings, gearbox and accessory-drive cases, hydraulic and pneumatic valve bodies, instrument and avionics enclosures and permanent-mould covers and manifolds. In short: most ductile Mg casting; pressure-tight aerospace castings; solution-treated T4 supply.
What is the yield strength of AZ81A?
AZ81A has a typical yield strength of 83 MPa (12 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 99% of magnesium alloy grades. Strength varies by condition: see the 2 listed tempers.
Is AZ81A easy to machine?
Yes — machinability is rated excellent (95/100, better than 54% of magnesium alloy grades). Outstanding machinability — very high speeds, low cutting forces, sharp positive-rake tools, no coolant containing water where possible, and strict chip/fines fire control (never water-quench a Mg fire).
Can AZ81A be welded?
Yes — weldability is rated good (62/100). GTAW/GMAW weldable with AZ92A or AZ101A filler; preheat 250–300 °C for heavy sections, then re-solution treat (T4) to restore ductility and relieve stress in the HAZ.
What surface finishes work on AZ81A?
Always apply a chromate-free conversion coat or Mg anodic/PEO coating (Dow 17, HAE) plus epoxy primer/topcoat; isolate from steel and aluminium fasteners to prevent galvanic attack.
Can AZ81A be formed, bent or molded?
Sand and permanent-mold casting alloy with good fluidity and pressure tightness; needs melt protection (SF6-free cover gas), grain refinement by superheat, and generous fillets to avoid hot tearing — no cold forming.
What is the maximum service temperature of AZ81A?
AZ81A is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between AZ81A-T4 and AZ81A-F?
T4 is the default condition — the standard supply condition for AZ81A — best combination of tensile strength, elongation and impact toughness for pressure-tight aerospace sand castings. F: pick only for non-critical castings or when the part is to be heat treated later; ductility is low because of the coarse Mg17Al12 network. Yield strength is 83 MPa in T4 versus 85 MPa in F.
How much does AZ81A cost?
AZ81A is a premium-cost magnesium alloy ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM B80 — Magnesium-Alloy Sand Castings — ASTM International (2015)
- SAE AMS 4453 / UNS M11810 designation records — SAE International (2018)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Specialty Handbook: Magnesium and Magnesium Alloys — ASM International (1999)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.