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Magnesium Alloy AM50A vs AZ91D

Magnesium Alloy · grade comparison

Magnesium Alloy AM50A and AZ91D are both magnesium alloy grades. AZ91D is the stronger of the two: yield strength 160 MPa (23.2 ksi) against 125 MPa (18.1 ksi) for AM50A, about 28% more. In exchange, AM50A is the more ductile: elongation 12% versus 3% for AZ91D, and AZ91D is harder (75 HV vs 65 HV). On the shop floor, AZ91D welds better (fair vs poor).

AM50AChoose it when the part is bent, formed or impact-loaded.

AZ91DChoose it when strength drives the design, or when it will be welded.

AM50A vs AZ91D: properties

AM50AAZ91D

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Yield Strength (0.2% offset)

125 MPa18.1 ksi
160 MPa23.2 ksi

Elongation at Break

12%
3%

Compressive Strength

250 MPa36.3 ksi
165 MPa23.9 ksi

Fatigue Strength (Endurance Limit)

70 MPa10.2 ksi
97 MPa14.1 ksi

Fracture Toughness (K_IC)

15 MPa·√m13.7 ksi·√in
13 MPa·√m11.8 ksi·√in

Charpy V-Notch Impact (RT)

6 J4.4 ft·lbf
2 J1.6 ft·lbf

Hardness, Brinell

60 HB
63 HB

Hardness, Vickers

65 HV
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 · Tensile Strength (Ultimate) 230 MPa33.4 ksi · Shear Strength 140 MPa20.3 ksi

Physical

Density and transition temperatures.

Density

1.77 g/cm³0.06 lb/in³
1.81 g/cm³0.07 lb/in³

Melting Point (Solidus)

543°C1,009 °F
470°C878 °F

Liquidus Temperature

620°C1,148 °F
595°C1,103 °F

Thermal

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

Thermal Conductivity

65 W/m·K37.6 BTU/hr·ft·°F
72 W/m·K41.6 BTU/hr·ft·°F

Latent Heat of Fusion

360 J/g155 BTU/lb
373 J/g160 BTU/lb

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 · Max Service Temperature (continuous) 120°C248 °F · Min Service Temperature -60°C-76 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

13 % IACS
12.2 % IACS

Electrical Resistivity

1.25×10⁻⁷ Ω·m4.92 µΩ·in
1.41×10⁻⁷ Ω·m5.55 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-1.6 V
-1.55 V

Same in both: Corrosion Resistance 30 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

95 / 100
98 / 100

Weldability

30 / 100
40 / 100

Formability (cold)

12 / 100
15 / 100

Same in both: Machinability Rating (AISI 1212 = 100 %) 400% · Castability 92 / 100 · Brazeability / Solderability 20 / 100 · Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

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

Embodied Carbon (primary production)

26 kg CO₂/kg
32 kg CO₂/kg

Same in both: Embodied Water 500 L/kg59.9 gal/lb · Typical Recycled Content 35%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

130 kN·m/kg
127 kN·m/kg

Specific Stiffness (E / density)

25.4 MN·m/kg
24.9 MN·m/kg

Modulus of Resilience

174 kJ/m³
284 kJ/m³

Thermal Diffusivity

36 mm²/s
39 mm²/s

Thermal Shock Resistance Index

13
14

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 scaleAZ91DAM50A

Manufacturing and finishing

CapabilityAM50AAZ91D
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

AM50A vs AZ91D — frequently asked

Is AZ91D stronger than AM50A?

Yes. AZ91D has a typical yield strength of 160 MPa (23.2 ksi) against 125 MPa (18.1 ksi) for AM50A — about 28% more. Tensile strength is 230 MPa (33.4 ksi) vs 230 MPa (33.4 ksi).

Which is cheaper, AM50A 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, AM50A or AZ91D?

AZ91D. Its weldability rates fair (40/100) against poor (30/100) for AM50A.

Ready to make it?

Upload a CAD file and FabDigit prices the part in AM50A 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.