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Magnesium Alloy AZ91D vs ZM1

Magnesium Alloy · grade comparison

Magnesium Alloy AZ91D and ZM1 are both magnesium alloy grades. ZM1 is the stronger of the two: tensile strength 275 MPa (39.9 ksi) against 230 MPa (33.4 ksi) for AZ91D, about 20% more. ZM1 is the more ductile: elongation 8% versus 3% for AZ91D, and ZM1 is harder (70 HB vs 63 HB). ZM1 runs hotter in service (150°C vs 120°C continuous) and ZM1 conducts heat better (117 W/m·K vs 72 W/m·K). On the shop floor, AZ91D welds better (fair vs poor) and AZ91D sits in a lower cost tier (standard, $$) than ZM1 (premium, $$$).

AZ91DChoose it when it will be welded, or when cost is the deciding factor.

ZM1Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

AZ91D vs ZM1: properties

AZ91DZM1

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

17 GPa2.5 Msi
16.5 GPa2.4 Msi

Tensile Strength (Ultimate)

230 MPa33.4 ksi
275 MPa39.9 ksi

Yield Strength (0.2% offset)

160 MPa23.2 ksi
165 MPa23.9 ksi

Elongation at Break

3%
8%

Compressive Strength

165 MPa23.9 ksi
300 MPa43.5 ksi

Shear Strength

140 MPa20.3 ksi
170 MPa24.7 ksi

Fatigue Strength (Endurance Limit)

97 MPa14.1 ksi
85 MPa12.3 ksi

Charpy V-Notch Impact (RT)

2 J1.6 ft·lbf
3 J1.8 ft·lbf

Hardness, Brinell

63 HB
70 HB

Hardness, Vickers

75 HV
—

Same in both: Elastic (Young's) Modulus 45 GPa6.5 Msi · Bulk Modulus 45 GPa6.5 Msi · Poisson's Ratio 0.35 · Fracture Toughness (K_IC) 13 MPa·√m11.8 ksi·√in

Physical

Density and transition temperatures.

Melting Point (Solidus)

470°C878 °F
550°C1,022 °F

Liquidus Temperature

595°C1,103 °F
640°C1,184 °F

Same in both: Density 1.81 g/cm³0.07 lb/in³

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

72 W/m·K41.6 BTU/hr·ft·°F
117 W/m·K67.6 BTU/hr·ft·°F

Specific Heat Capacity

1,020 J/kg·K0.24 BTU/lb·°F
1,000 J/kg·K0.24 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

26 µm/m·K14.4 µin/in·°F
27.1 µm/m·K15.1 µin/in·°F

Latent Heat of Fusion

373 J/g160 BTU/lb
340 J/g146 BTU/lb

Max Service Temperature (continuous)

120°C248 °F
150°C302 °F

Min Service Temperature

-60°C-76 °F
-70°C-94 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

12.2 % IACS
28 % IACS

Electrical Resistivity

1.41×10⁻⁷ Ω·m5.55 µΩ·in
6.2×10⁻⁸ Ω·m2.44 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

30 / 100
18 / 100

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

98 / 100
95 / 100

Weldability

40 / 100
30 / 100

Castability

92 / 100
60 / 100

Same in both: Machinability Rating (AISI 1212 = 100 %) 400% · Formability (cold) 15 / 100 · Brazeability / Solderability 20 / 100 · Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

320 MJ/kg137,575 BTU/lb
300 MJ/kg128,977 BTU/lb

Embodied Carbon (primary production)

32 kg CO₂/kg
35 kg CO₂/kg

Typical Recycled Content

35%
25%

Same in both: Embodied Water 500 L/kg59.9 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

127 kN·m/kg
152 kN·m/kg

Modulus of Resilience

284 kJ/m³
303 kJ/m³

Thermal Diffusivity

39 mm²/s
64.6 mm²/s

Thermal Shock Resistance Index

14
26

Same in both: Specific Stiffness (E / density) 24.9 MN·m/kg

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.

701001502001.41.51.61.71.8Density (g/cm³)Yield strength (MPa) — log scaleAZ91DZM1

Manufacturing and finishing

CapabilityAZ91DZM1
CNC machiningYes—
Casting & forgingYes—
Default conditionAs Cast—
Relative cost$$ Standard$$$ Premium
Min. machined wall0.8 mm—
Best machined surfaceRa 0.8 µm—
Anodizing Type IIYes—
Chem Film (Alodine)Yes—
E-CoatingYes—
Hard Anodize Type III w/ PTFEYes—
Hard Anodizing Type IIIYes—
PaintingYes—
Powder CoatingYes—

AZ91D vs ZM1 — frequently asked

Is ZM1 stronger than AZ91D?

Yes. ZM1 has a typical tensile strength of 275 MPa (39.9 ksi) against 230 MPa (33.4 ksi) for AZ91D — about 20% more.

Which is cheaper, AZ91D or ZM1?

AZ91D is the lower-cost material: it sits in the standard tier ($$) while ZM1 is premium ($$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which welds better, AZ91D or ZM1?

AZ91D. Its weldability rates fair (40/100) against poor (30/100) for ZM1.

Ready to make it?

Upload a CAD file and FabDigit prices the part in AZ91D and ZM1 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.