EQ21A (EQ21A-T6, M18330) Magnesium

EQ21A magnesium is an alloy of magnesium. It is typically furnished in the T6 temper. EQ21A is the ASTM designation for this material. M18330 is the UNS number.

Material Properties

Brinell Hardness80

Compressive (Crushing) Strength350 MPa (51 x 103 psi)

Density2.0 g/cm3 (120 lb/ft3)

Elastic (Young's, Tensile) Modulus44 GPa (6.4 x 106 psi)

Electrical Conductivity25 % IACS

Electrical Resistivity Order of Magnitude-7 10x Ω-m

Elongation at Break2.4 %

Fatigue Strength (Endurance Limit)85 MPa (12 x 103 psi)

Fracture Toughness16 MPa-m1/2

Melting Onset (Solidus)560 °C (1040 °F)

Modulus of Resilience (Unit Resilience)410 kJ/m3

Poisson's Ratio0.29

Shear Strength150 MPa (22 x 103 psi)

Solidification (Pattern Maker's) Shrinkage1.3 %

Specific Heat Capacity1000 J/kg-K

Strength to Weight Ratio130 kN-m/kg

Tensile Strength: Ultimate (UTS)250 MPa (36 x 103 psi)

Tensile Strength: Yield (Proof)190 MPa (28 x 103 psi)

Thermal Conductivity110 W/m-K

Thermal Diffusivity55 m2/s

Thermal Expansion27 µm/m-K

Unit Rupture Work (Ultimate Resilience)5.5 MJ/m3

The length of each bar compares the given value to the highest value in the database.

Alloy Composition

Magnesium (Mg)93.9 to 96.8 %

Unspecified Rare Earths1.5 to 3.0 %

Silver (Ag)1.3 to 1.7 %

Zirconium (Zr)0.4 to 1.0 %

Residuals0 to 0.3 %

Copper (Cu)0.050 to 0.1 %

Nickel (Ni)0 to 0.010 %

Further Reading

ASTM B199: Standard Specification for Magnesium-Alloy Permanent Mold Castings

ASTM B403: Standard Specification for Magnesium-Alloy Investment Castings

ASTM B80: Standard Specification for Magnesium-Alloy Sand Castings

Environmental Degradation of Advanced and Traditional Engineering Materials, Lloyd H. Hihara et al., 2014.