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Magnesium Alloy AM60B vs AZ91B

Magnesium Alloy · grade comparison

Magnesium Alloy AM60B and AZ91B are both magnesium alloy grades. AZ91B is the stronger of the two: yield strength 150 MPa (21.8 ksi) against 130 MPa (18.9 ksi) for AM60B, about 15% more. In exchange, AM60B is the more ductile: elongation 8% versus 3% for AZ91B. AZ91B conducts heat better (72 W/m·K vs 61 W/m·K). On the shop floor, AM60B welds better (fair vs poor).

AM60BChoose it when the part is bent, formed or impact-loaded, or when it will be welded.

AZ91BChoose it when strength drives the design.

AM60B vs AZ91B: properties

AM60BAZ91B

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

225 MPa32.6 ksi
230 MPa33.4 ksi

Yield Strength (0.2% offset)

130 MPa18.9 ksi
150 MPa21.8 ksi

Elongation at Break

8%
3%

Compressive Strength

130 MPa18.9 ksi
330 MPa47.9 ksi

Fatigue Strength (Endurance Limit)

70 MPa10.2 ksi
97 MPa14.1 ksi

Fracture Toughness (K_IC)

16 MPa·√m14.6 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

62 HB
63 HB

Hardness, Vickers

—
70 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 · Shear Strength 140 MPa20.3 ksi

Physical

Density and transition temperatures.

Density

1.8 g/cm³0.07 lb/in³
1.81 g/cm³0.07 lb/in³

Melting Point (Solidus)

540°C1,004 °F
470°C878 °F

Liquidus Temperature

615°C1,139 °F
595°C1,103 °F

Thermal

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

Thermal Conductivity

61 W/m·K35.2 BTU/hr·ft·°F
72 W/m·K41.6 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

25.6 µm/m·K14.2 µin/in·°F
26 µm/m·K14.4 µin/in·°F

Latent Heat of Fusion

373 J/g160 BTU/lb
370 J/g159 BTU/lb

Same in both: Specific Heat Capacity 1,020 J/kg·K0.24 BTU/lb·°F · Max Service Temperature (continuous) 120°C248 °F · Min Service Temperature -100°C-148 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

13.5 % IACS
12 % 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

Corrosion Resistance

30 / 100
12 / 100

Manufacturability

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

Machinability Rating (AISI 1212 = 100 %)

500%
400%

Weldability

40 / 100
30 / 100

Formability (cold)

20 / 100
10 / 100

Castability

92 / 100
95 / 100

Brazeability / Solderability

20 / 100
15 / 100

Same in both: Machinability 95 / 100 · Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

330 MJ/kg141,875 BTU/lb
310 MJ/kg133,276 BTU/lb

Embodied Carbon (primary production)

26 kg CO₂/kg
30 kg CO₂/kg

Typical Recycled Content

30%
40%

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

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

125 kN·m/kg
127 kN·m/kg

Specific Stiffness (E / density)

25 MN·m/kg
24.9 MN·m/kg

Modulus of Resilience

188 kJ/m³
250 kJ/m³

Thermal Diffusivity

33.2 mm²/s
39 mm²/s

Thermal Shock Resistance Index

12
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 scaleAM60BAZ91B

Manufacturing and finishing

CapabilityAM60BAZ91B
CNC machiningYes—
Default conditionAs Cast—
Relative cost$$ Standard$$ Standard
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—

AM60B vs AZ91B — frequently asked

Is AZ91B stronger than AM60B?

Yes. AZ91B has a typical yield strength of 150 MPa (21.8 ksi) against 130 MPa (18.9 ksi) for AM60B — about 15% more. Tensile strength is 230 MPa (33.4 ksi) vs 225 MPa (32.6 ksi).

Which is cheaper, AM60B or AZ91B?

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, AM60B or AZ91B?

AM60B. Its weldability rates fair (40/100) against poor (30/100) for AZ91B.

Ready to make it?

Upload a CAD file and FabDigit prices the part in AM60B and AZ91B 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.