Magnesium Alloy AZ81A-F (As fabricated)
Temper
ASTM AZ81A · UNS M11810
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.
Values for the F condition
Other AZ81A tempers and conditions
AZ81A is listed in 2 conditions; see the grade overview at AZ81A.
- T4
- F
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 |
FThis page 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-F?
AZ81A-F is AZ81A in the F temper — 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. AZ81A-F has a yield strength of 85 MPa (12.3 ksi) and a tensile strength of 160 MPa (23.2 ksi) — weaker than 97% of magnesium alloy grades. Elongation at break is 3% and the elastic modulus is 45 GPa (6.53 Msi). AZ81A-F 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). T4 is the default condition FabDigit quotes; F is available on request or by drawing note.
Limitations
- Low strength — 85 MPa (12.3 ksi), worse than 97% of magnesium alloy grades
- Hard to polish — 45/100, worse than 93% of magnesium alloy grades
- Limited ductility — 3%, worse than 85% of magnesium alloy grades
- Limited service temperature — 120°C (248 °F), worse than 78% of magnesium alloy grades
AZ81A-F properties
Typical room-temperature values for AZ81A-F; 15 are specific to this condition. Other listed values are AZ81A reference data and may not represent this condition. Bars are the position among magnesium alloy grades.
Physical3
AZ81A-F 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-F has a yield strength of 85 MPa (12.3 ksi) and a tensile strength of 160 MPa (23.2 ksi) — weaker than 97% of magnesium alloy grades. Elongation at break is 3% and the elastic modulus is 45 GPa (6.53 Msi).
Thermal6
AZ81A-F is rated for continuous service to 120°C (248 °F). It conducts heat at 72 W/m·K (41.6 BTU/hr·ft·°F), worse than 69% of magnesium alloy grades. Thermal expansion is 26 µm/m·K (14.4 µin/in·°F).
Electrical3
AZ81A-F conducts electricity at 12.2 % IACS, worse than 70% of magnesium alloy grades.
Chemical & Environmental3
Corrosion resistance is poor (17/100), worse than 91% of magnesium alloy grades.
Sustainability4
Producing a kilogram of AZ81A-F 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-F's machinability is excellent (95/100, better than 54% of magnesium alloy grades); weldability good (60/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AZ81A-F
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.
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.
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 | — |
AZ81A-F — frequently asked
What is AZ81A-F used for?
AZ81A-F 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-F?
AZ81A-F has a typical yield strength of 85 MPa (12.3 ksi) and a tensile strength of 160 MPa (23.2 ksi) — weaker than 97% of magnesium alloy grades. Strength varies by condition: see the 2 listed tempers.
Is AZ81A-F 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-F be welded?
Yes — weldability is rated good (60/100). 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-F?
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-F 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-F?
AZ81A-F 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.