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Magnesium Alloy AM100A vs AZ91D

Magnesium Alloy · grade comparison

Magnesium Alloy AM100A and AZ91D are both magnesium alloy grades. AZ91D is the stronger of the two: yield strength 160 MPa (23.2 ksi) against 152 MPa (22 ksi) for AM100A, about 5% more. AZ91D is the more ductile: elongation 3% versus 1% for AM100A, and AM100A is harder (69 HB vs 63 HB). On the shop floor, AM100A welds better (good vs fair).

AM100AChoose it when it will be welded.

AZ91DChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

AM100A vs AZ91D: properties

AM100AAZ91D

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

275 MPa39.9 ksi
230 MPa33.4 ksi

Yield Strength (0.2% offset)

152 MPa22 ksi
160 MPa23.2 ksi

Elongation at Break

1%
3%

Compressive Strength

345 MPa50 ksi
165 MPa23.9 ksi

Shear Strength

145 MPa21 ksi
140 MPa20.3 ksi

Fatigue Strength (Endurance Limit)

76 MPa11 ksi
97 MPa14.1 ksi

Fracture Toughness (K_IC)

12 MPa·√m10.9 ksi·√in
13 MPa·√m11.8 ksi·√in

Charpy V-Notch Impact (RT)

1 J1 ft·lbf
2 J1.6 ft·lbf

Hardness, Brinell

69 HB
63 HB

Hardness, Vickers

—
75 HV

Same in both: Elastic (Young's) Modulus 45 GPa6.5 Msi · Shear Modulus 17 GPa2.5 Msi · Bulk Modulus 45 GPa6.5 Msi · Poisson's Ratio 0.35

Physical

Density and transition temperatures.

Melting Point (Solidus)

465°C869 °F
470°C878 °F

Liquidus Temperature

598°C1,108 °F
595°C1,103 °F

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

Thermal

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

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

25.2 µm/m·K14 µin/in·°F
26 µm/m·K14.4 µin/in·°F

Min Service Temperature

-100°C-148 °F
-60°C-76 °F

Same in both: Thermal Conductivity 72 W/m·K41.6 BTU/hr·ft·°F · Latent Heat of Fusion 373 J/g160 BTU/lb · Max Service Temperature (continuous) 120°C248 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

12 % IACS
12.2 % IACS

Electrical Resistivity

1.4×10⁻⁷ Ω·m5.51 µΩ·in
1.41×10⁻⁷ Ω·m5.55 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

20 / 100
30 / 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

96 / 100
98 / 100

Weldability

60 / 100
40 / 100

Formability (cold)

8 / 100
15 / 100

Castability

82 / 100
92 / 100

Polishability

45 / 100
55 / 100

Same in both: Machinability Rating (AISI 1212 = 100 %) 400% · Brazeability / Solderability 20 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

30 kg CO₂/kg
32 kg CO₂/kg

Typical Recycled Content

25%
35%

Same in both: Embodied Energy (primary production) 320 MJ/kg137,575 BTU/lb · Embodied Water 500 L/kg59.9 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

152 kN·m/kg
127 kN·m/kg

Modulus of Resilience

257 kJ/m³
284 kJ/m³

Thermal Diffusivity

39.8 mm²/s
39 mm²/s

Thermal Shock Resistance Index

17
14

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 scaleAZ91DAM100A

Manufacturing and finishing

CapabilityAM100AAZ91D
CNC machining—Yes
Casting & forging—Yes
Default condition—As Cast
Relative cost$$ Standard$$ Standard
Min. machined wall—0.8 mm
Best machined surface—Ra 0.8 µm
Anodizing Type II—Yes
Chem Film (Alodine)—Yes
E-Coating—Yes
Hard Anodize Type III w/ PTFE—Yes
Hard Anodizing Type III—Yes
Painting—Yes
Powder Coating—Yes

AM100A vs AZ91D — frequently asked

Is AZ91D stronger than AM100A?

Yes. AZ91D has a typical yield strength of 160 MPa (23.2 ksi) against 152 MPa (22 ksi) for AM100A — about 5% more. Tensile strength is 230 MPa (33.4 ksi) vs 275 MPa (39.9 ksi).

Which is cheaper, AM100A or AZ91D?

Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which welds better, AM100A or AZ91D?

AM100A. Its weldability rates good (60/100) against fair (40/100) for AZ91D.

Ready to make it?

Upload a CAD file and FabDigit prices the part in AM100A and AZ91D 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.