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The Magnesium Home Page
 Properties of Cast Magnesium Alloys

The following information is reproduced with kind permission of ASM International.


The information on alloy properties is restricted at the moment to cast AM60 and AZ91 alloys. Hopefully, other alloys will be able to be added in the future. To use the table below, just click on the X that corresponds to the alloy and property classification that you are after.

PROPERTY AM60 AZ91
Specifications X X
Chemical Composition X X
Applications X X
Mechanical Properties X X
Mass Characteristics X X
Thermal Properties X X
Electical Properties - X
Fabrication Characteristics X X
Corrosion Resistance X X

Cast Magnesium Alloys

AM60A, AM60B

Specifications

ASTM. Die castings: B 94
UNS numbers. AM60A: M10600. AM60B: M10603
Other. German: DIN 1729 3.5662

Chemical Composition

Composition limits of AM60A

5.5-6.5% Al
0.13% Mn min.
0.50% Si max.
0.35% Cu max.
0.22% Zn max.
0.03% Ni max.
balance Mg

Composition limits of AM60B

5.5 to 6.5 Al
0.25% Mn min.
0.10% Si max.
0.22% Zn max.
0.005% Fe max.
0.010% Cu max.
0.002% Ni max.
0.003% max. other (total)
balance Mg.

If the Mn content is less than 0.25% or the Fe content in AM60B exceeds 0.005%, then the Fe-Mn ratio will not exceed 0.010 and corrosion resistance will rapidly decrease.

Consequence of exceeding impurity limits

Corrosion resistance decreases with increasing Fe, Cu, or Ni content.

Applications

Typical uses

Die casting alloy used as-cast (F) temper for production of automotive wheels and other parts requiring good elongation and toughness combined with reasonable yield and tensile properties.

Mechanical Properties

Tensile properties

F temper:
Tensile strength: 220 MPa (32 ksi)
Yield strength: 130 MPa (19 ksi)
Elongation: 6% in 50 mm (2 in.)

Compressive yield strength

F temper: 130 MPa (19ksi)

Poisson’s ratio

0.35

Elastic modulus

Tension, 45 GPa (6.5 x 106 psi)

Mass Characterisitics

Density

1.8 g/cm3 (0.065 lb/in.3) at 20ºC (68ºF).

Thermal Properties

Liquidus temperature

615ºC (1140ºF)

Solidus temperature

540ºC (1005ºF).

Coefficient of linear thermal expansion

25.6 µm/m.K (14.2 µin/in.ºF) at 20 to 100ºC (68 to 212ºF).

Thermal conductivity

62 W/m.K (36 Btu/ft.h.ºF) at 20ºC (68ºF).

Fabrication Characteristics

Casting temperature

650 to 695oC (1200 to 1280oF)

Weldability

Not weldable.

Corrosion Resistance

ASTM B 177 salt spray test

AM60B: <0.13 mg/cm2 /day (<20 mils/yr).

AZ91A, AZ91B, AZ91C, AZ91D, AZ91E

Specifications

AMS

Die castings: AZ91A, 4490.
Sand castings: AZ91C, 4437; AZ91E, 4446.

ASTM

Die castings: AZ91A, AZ91B, and AZ91D; B 94.
Sand castings: AZ91C and AZ91E; B 80.
Permanent mold castings: AZ9C and AZ91E; B 199.
Investment castings: AZ91C and AZ91E; B 403.
Ingot: B 93.

SAE

J465. Former SAE alloy numbers:
AZ91A, 501;
AZ91B, 501A;
AZ91C, 504.

UNS numbers

AZ91A: M11910.
AZ91B: M11912.
AZ91C: M11914.
AZ91D: M11916.
AZ91E: M11921.

Government

Die castings: AZ91A, QQ-M38.
Permanent mold castings: AZ91C, QQ-M-55 and MIL-M-46062.
Sand castings: AZ91C, QQ-M-56, and MIL-M-46062.

Other

Elektron: AZ91.
British: BS 2970 MAG3.
French: AIR 3380 G-AZ91.
German: DIN 1729 3.5912.

Chemical Composition

Composition limits of AZ91A

8.3-9.7% Al
0.13% Mn min.
0.35-1.0% Zn
0.50% Si max.
0.10% Cu max.
0.03% Ni max.
0.30% max. other
balance Mg.

Composition limits of AZ91B

8.3-9.7% Al
0.13% Mn min.
0.35-1.0% Zn
0.50% Si max.
0.35% Cu max.
0.03% Ni max.
0.30% max. other
balance Mg.

Composition limits of AZ91C

8.1-9.3% Al
0.13% Mn min.
0.40-1.0% Zn
0.30% Si max.
0.10% Cu max.
0.01% Ni max.
0.3% max. other (total)
balance Mg.

Composition limits of AZ91D

8.3-9.7% Al
0.15% Mn min.
0.35-1.0% Zn
0.10% Si max.
0.005% Fe max.
0.030% Cu max.
0.002% Ni max.
0.02% max. other (each)
balance Mg.

Composition limits of AZ91E

8.1-9.3% Al
0.17-0.35% Mn
0.4-1.0% Zn
0.20% Si max.
0.005% Fe max.
0.015% Cu max.
0.0010% Ni max.
0.01% max. other (each)
0.30% max. other (total)

Consequence of exceeding impurity limits

Applications

Typical uses

Corrosion Resistance

ASTM B 117 Salt spray test

AZ91D: less than 0.13 mg/cm2/day (less than 10 mils/yr).
AZ91E-T6: less than 0.63 mg/cm2/day (less than 50 mils/yr).

Mechanical Properties

Tensile properties

See Tables
27 and 28.

Shear strength

AZ91A, AZ91B, and AZ91D: F temper; 140 Mpa (20 ksi)

Compressive yield strength

See Table 27.

Bearing properties

See Table 27.

Hardness

See Table 27.

Poisson’s ratio

0.35

Elastic modulus

Tension, 45 GPa (6.5 x 106 psi)
Shear, 17 GPa (2.4 x 106 psi)

Impact strength

See Table 27.

Fatigue strength

R.R. Moore type tests.
At 5 x 108 cycles: AZ91A, AZ91B, and AZ91D (F temper): 97 MPa (14 ksi)
At 1 x 108 cycles: AZ91C and AZ91E: 80-95 MPa (12 to 14 ksi).

Mass Characteristics

Density

1.81 g/cm3 (0.066 lb/in.3) at 20ºC (68ºF).

Thermal Properties

Liquidus temperature

595ºC (1105ºF)

Solidus temperature

470ºC (875ºF)

Coefficient of linear thermal expansion

26 µm/m.K (14 µin./in.F) at 20 to 100ºC (68 to 212ºF).

Specific heat

1.05 kJ/kg.K (0.25 Btu/lb.ºF) at 20ºC (68ºF).

Latent heat of fusion

373 kJ/kg (160 Btu/lb)

Thermal conductivity

72 W/m.K (41.8 Btu/ft.h.ºF) at 100 to 300ºC (212 to 572ºF).

Incipient melting temperature

421ºC (790ºF)

Electrical Properties

Electrical conductivity

AZ91A:
F temper, 10.1% IACS.
AZ91C and AZ91E:
F temper, 11.5%, IACS
T4 temper, 9.9%, IACS
T6 temper, 11.2% IACS

Electrical resistivity

AZ91A, AZ91B, and AZ91D:
F temper, 170 nohm.m
AZ91C and AZ91E:
F temper, 150 nohm.m
T4 temper, 175 nohm.m
T6 temper, 151.5 nohm.m

Electrolyte solution potential

1.58 V versus saturated calomel electrode.

Hydrogen overvoltage

As-cast, 0.40 V

Fabrication Characteristics

Casting temperature

AZ91C and AZ91E:
Sand castings, 705 to 845ºC (1300 to 1550ºF)
Permanent mold castings, 650 to 815ºC (1200 to 1500ºF)
AZ91A, AZ91B and AZ91D:
Die castings, 625 to 700 ºC (1160 to 1290ºF)

Weldability

AZ91C and AZ91E can be readily welded by the gas-shielded arc process using AZ91C or AZ92A rod; stress relief required.
AZ91A, AZ91B and AZ91D not weldable.

Hot-shortness temperature

400ºC (750ºF)

Table 27 - Typical room temperature mechanical properties of AZ91 castings

AZ91A,B,D AZ91C,E
Property F Temper F Temper T4 Temper T6 Temper
Tensile strength, MPa (ksi) 230 (33) 165 (24) 275 (40) 275 (40)
Tensile yield strength, MPa (ksi) 150 (22) 97 (14) 90 (13) 145 (21)
Elongation in 50 mm (2 in.), % 3 2.5 15 6
Compressive yield strength at 0.2% offset, MPa (ksi) 165 (24) 97 (14) 90 (13) 130 (19)
Ultimate bearing strength, MPa (ksi) - 415 (60) 415 (60) 515 (75)
Bearing yield strength, MPa (ksi) - 275 (40) 305 (44) 360 (52)
Hardness, HB 63 60 55 70
Hardness, HRE 75 66 62 77
Charpy V-notch impact strength, J (ft.lbf) 2.7 (2.0) 0.79 (0.58) 4.1 (3.0) 1.4 (1.0)

Table 28 - Typical tensile properties of AZ91C-T6 sand castings at elevated temperatures

Testing Temperature Tensile Strength Yield Strength Elongation
ºC ºF MPa ksi MPa ksi in 50 mm %
150 300 185 27 97 14 40
240 400 115 27 83 12 40

The information displayed on this page is indicative only. The editors do not take any responsibility for the accuracy and relevance of the information supplied and expressly exclude liability for and damage, loss or injury that a person may suffer as a result of using the above information.

For more information and comments about this page please contact Nigel Ricketts