Elektron® 21

Our Flagship High Strength Fully Heat Treatable Magnesium based Casting Alloy.

For use at temperatures up to 200˚C, this alloy has excellent corrosion resistance characteristics and castability, making it the suitable material for a range of aerospace applications.

Luxfer MEL Technologies has developed this lightweight, high performance alloy for aerospace applications. It is designed to provide superior mechanical properties and improved corrosion resistance together with good castability.

AMS 4429
UNS M12310
ISO 16220 MC65410

Zinc:   0.2–0.5%
Neodymium:   2.6–3.1%
Gadolinium:   1.0–1.7%
Zirconium:   Saturated
Magnesium:   Balance

Castings are given the following T6 heat treatment to obtain optimum mechanical properties.

Solution treat for 8 hours at 520˚C (970˚F), Hot water quench using water at 60–80˚C (140–175˚F) or polymer quench, Age for 16 hours at 200˚C (400˚F), Air cool.

Specific gravity:   1.82
Coefficient of thermal expansion:   26.3 x 10-6K-1
Thermal conductivity:   116 Wm-1K-1
Specific heat:   1,086 Jkg-1K-1
Electrical resistivity:   94.6 nΩm
Modulus of elasticity: 44.8 x 103 MPa
Poissons ratio:   0.27
Melting range:   545–640˚C
Brinell hardness:     65–75

Minimum specification tensile properties.

0.2% proof stress:   145 MPa
Tensile strength:   248 MPa
Elongation:   2%


Excellent castability as a consequence of low oxidation characteristics.

Fine-grained microstructure.

Pressure tight.

Pattern Makers Shrinkage Factor



Weldable by the tungsten arc inert gas process (TIG) with a filler rod of a similar composition. Castings should be heat treated after welding to obtain optimum properties.


Elektron® 21 castings, like all magnesium alloy castings, machine faster than any other metal. Providing the geometry of the part allows, the limiting factor is the power and speed of the machine rather than the quality of the tool material. The power required per cubic centimetre of metal removed varies from 9 to 14 watts per minute depending on the operation.

Surface Treatment

All the normal chromating, anodising and finishing treatments are applicable.

Corrosion Resistance

ASTM B117 salt spray test corrosion rate for base metal:
<1.14 mg/cm2/day
<90 mpy

Typical tensile properties

0.2% proof stress:   170 MPa
Tensile strength:   280 MPa
Elongation:   5%

Typical compressive properties

0.2% proof stress:   168 MPa
Ultimate strength:   367 MPa

Typical shear properties

Ultimate stress:   172 MPa

Fracture toughness

KIC:   15.5 MPa m1/2

Fatigue properties

Pull-pull fatigue: R = 0.1
5 x 107 cycles
115–120 MPa

Low temperature mechanical properties

Typical mechanical properties at -35˚C

Elongation:   7%
Ultimate tensile strength:   270 MPa
Impact value (notched):   1.7 J

Elevated Temperature Mechanical Properties

Typical Tensile Properties

Figure 1. Effect of temperature on tensile properties.

Creep Properties

Figure 2. Stress /time relationship at 200˚C (0.1% creep strain).

Send an Inquiry or Request a Quote

Ross Baird

Sector Manager Aerospace Advanced Castings