Magnesium Alloy ZM21-F vs ZM21-O
Magnesium Alloy · ZM21 temper comparison
ZM21-F and ZM21-O are two conditions of the same magnesium alloy grade, ZM21: F (as fabricated) versus O (annealed). The chemistry is identical, so every difference below comes from the condition. ZM21-F is the stronger of the two: yield strength 160 MPa (23.2 ksi) against 140 MPa (20.3 ksi) for ZM21-O, about 14% more. In exchange, ZM21-O is the more ductile: elongation 19% versus 13% for ZM21-F, and ZM21-F is harder (50 HB vs 45 HB).
ZM21-FChoose it when strength drives the design.
ZM21-OChoose it when the part is bent, formed or impact-loaded.
ZM21-F vs ZM21-O: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all magnesium alloy grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all magnesium alloy grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Same in both: Shear Modulus 17 GPa2.5 Msi · Bulk Modulus 45 GPa6.5 Msi · Poisson's Ratio 0.35
Physical
Density and transition temperatures.
Same in both: Density 1.78 g/cm³0.06 lb/in³ · Melting Point (Solidus) 605°C1,121 °F · Liquidus Temperature 645°C1,193 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: Specific Heat Capacity 1,020 J/kg·K0.24 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 26 µm/m·K14.4 µin/in·°F · Latent Heat of Fusion 370 J/g159 BTU/lb · Max Service Temperature (continuous) 120°C248 °F · Min Service Temperature -100°C-148 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -1.55 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Same in both: Machinability Rating (AISI 1212 = 100 %) 300% · Castability 35 / 100 · Brazeability / Solderability 25 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 350 MJ/kg150,473 BTU/lb · Embodied Carbon (primary production) 36 kg CO₂/kg · Embodied Water 500 L/kg59.9 gal/lb · Typical Recycled Content 30%
Strength versus weight
Yield strength against density for every magnesium alloy grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
ZM21-F vs ZM21-O — frequently asked
Is ZM21-F stronger than ZM21-O?
Yes. ZM21-F has a typical yield strength of 160 MPa (23.2 ksi) against 140 MPa (20.3 ksi) for ZM21-O — about 14% more. Tensile strength is 250 MPa (36.3 ksi) vs 240 MPa (34.8 ksi).
Which condition does FabDigit quote by default, F or O?
O is the default ZM21 condition in the FabDigit quote flow. The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
When should I choose ZM21-F over ZM21-O?
Pick ZM21-F when strength drives the design. Pick ZM21-O when the part is bent, formed or impact-loaded.
Ready to make it?
Upload a CAD file and FabDigit prices the part in ZM21-F and ZM21-O side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.