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Magnesium Alloy AZ63A vs AZ91D

Magnesium Alloy · grade comparison

Magnesium Alloy AZ63A and AZ91D are both magnesium alloy grades. AZ91D is the stronger of the two: yield strength 160 MPa (23.2 ksi) against 130 MPa (18.9 ksi) for AZ63A, about 23% more. In exchange, AZ63A is the more ductile: elongation 5% versus 3% for AZ91D, and AZ63A is harder (73 HB vs 63 HB). AZ63A conducts electricity better (14 % IACS vs 12.2 % IACS). On the shop floor, AZ63A welds better (good vs fair).

AZ63AChoose it when the part is bent, formed or impact-loaded, or when it will be welded.

AZ91DChoose it when strength drives the design.

AZ63A vs AZ91D: properties

AZ63AAZ91D

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)

130 MPa18.9 ksi
160 MPa23.2 ksi

Elongation at Break

5%
3%

Compressive Strength

110 MPa16 ksi
165 MPa23.9 ksi

Shear Strength

145 MPa21 ksi
140 MPa20.3 ksi

Fatigue Strength (Endurance Limit)

80 MPa11.6 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)

3 J2.2 ft·lbf
2 J1.6 ft·lbf

Hardness, Brinell

73 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.

Density

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

Melting Point (Solidus)

455°C851 °F
470°C878 °F

Liquidus Temperature

610°C1,130 °F
595°C1,103 °F

Thermal

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

Thermal Conductivity

76 W/m·K43.9 BTU/hr·ft·°F
72 W/m·K41.6 BTU/hr·ft·°F

Specific Heat Capacity

1,050 J/kg·K0.25 BTU/lb·°F
1,020 J/kg·K0.24 BTU/lb·°F

Min Service Temperature

-100°C-148 °F
-60°C-76 °F

Same in both: Thermal Expansion (CTE, 20–100 °C) 26 µm/m·K14.4 µin/in·°F · Latent Heat of Fusion 373 J/g160 BTU/lb · Max Service Temperature (continuous) 120°C248 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

14 % IACS
12.2 % IACS

Electrical Resistivity

1.22×10⁻⁷ Ω·m4.8 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)

-1.57 V
-1.55 V

Corrosion Resistance

22 / 100
30 / 100

Manufacturability

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

Machinability

95 / 100
98 / 100

Weldability

65 / 100
40 / 100

Castability

80 / 100
92 / 100

Brazeability / Solderability

25 / 100
20 / 100

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

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

330 MJ/kg141,875 BTU/lb
320 MJ/kg137,575 BTU/lb

Embodied Carbon (primary production)

27 kg CO₂/kg
32 kg CO₂/kg

Typical Recycled Content

30%
35%

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

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

149 kN·m/kg
127 kN·m/kg

Specific Stiffness (E / density)

24.5 MN·m/kg
24.9 MN·m/kg

Modulus of Resilience

188 kJ/m³
284 kJ/m³

Thermal Diffusivity

39.3 mm²/s
39 mm²/s

Thermal Shock Resistance Index

18
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 scaleAZ91DAZ63A

Manufacturing and finishing

CapabilityAZ63AAZ91D
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

AZ63A vs AZ91D — frequently asked

Is AZ91D stronger than AZ63A?

Yes. AZ91D has a typical yield strength of 160 MPa (23.2 ksi) against 130 MPa (18.9 ksi) for AZ63A — about 23% more. Tensile strength is 230 MPa (33.4 ksi) vs 275 MPa (39.9 ksi).

Which is cheaper, AZ63A 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, AZ63A or AZ91D?

AZ63A. Its weldability rates good (65/100) against fair (40/100) for AZ91D.

Ready to make it?

Upload a CAD file and FabDigit prices the part in AZ63A 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.