Elektron® RZ5

The versatility of this alloy makes it of interest to a wide range of designers dealing with aerospace, automotive, military and electronic applications. Castings in Elektron® RZ5 are found in a wide range of applications including:

• Helicopter gearboxes
• Performance car components
• Video cameras
• Military equipment
• Computer parts
• Aircraft engines
• Power tools
• Vibration testing equipment
• Aircraft components
• Motorcycle wheels

• ASTM B80 ZE41A-T5 AMS 4439
• MIL-M-46062
• UNS M16410
• MMPDS BS 2L.128
• BS2970 MAG5-TE AIR 3380 RZ5
• AFNOR G-Z4TR DIN 1729 3.5101
• Aircraft Number 3.6104 UNAVIA 816-02 EN 1753
• EN MB 35110

• Zinc: 3.5–5.0%
• Rare earths: 0.8–1.7%
• Zirconium: 0.4–1.0%
• Magnesium: Balance

Optimum properties are achieved in the T5 condition after 2 hours at 330˚C followed by 10–16 hours at 170–180˚C. Satisfactory properties may be obtained from 1–6 hours at 325–360˚C. Water quenching is not required.

• Specific gravity: 1.84
• Coefficient of thermal expansion: 27.1x 10-6K-1
• Thermal conductivity: 109 Wm-1K-1
• Specific heat: 960 Jkg-1K-1
• Electrical resistivity: 68 nΩm
• Modulus of elasticity: 44.1 GPa
• Poissons ratio: 0.35
• Melting range: 510–640˚C
• Damping index: 1.0
• Brinell hardness: 55–70

• Minimum specification tensile properties
• BS 2L.128
• 0.2% proof stress: 135 MPa
• Tensile strength: 200 MPa

Castability

Castings will contain minimal microporosity and the tendency to hot cracking is low. Castings are pressure tight and may be welded.

Pattern makers shrinkage factor

1.3%

Weldability

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

Machining

Elektron® RZ5 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: 4–6mg/cm2/day
• 320–480mpy

Low temperature properties

• Mechanical properties at -196˚C:
• Elongation: 0.5%
• Ultimate tensile strength: 245MPa
• Impact value (unnotched): 0.7j

Typical tensile properties

• 0.2% proof stress: 148 MPa
• Tensile strength: 218 MPa
• Elongation: 4.5%

Typical compressive properties

• 0.2% proof stress: 130–150 MPa
• Ultimate strength: 330–365 MPa

Typical shear properties

Ultimate stress: 138 MPa

Fracture toughness

KIC: 15.1–16.3 MPa m1/2

Fatigue properties

Figure 1. Rotating bending fatigue tests on sand castings.

Figure 2. Fatigue crack growth.

Typical tensile properties

Figure 3. Effect of temperature on tensile properties.

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Creep properties

Figure 4. Stress / time relationship for specified creep strains at 100˚C.

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Figure 5. Stress / time relationship for specified creep strains at 150˚C

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Fatigue properties

Figure 6. Rotating bending fatigue tests.

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Table 1. Cut up properties on samples taken from actual castings.

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