MG · magnesium
Magnesium Alloy ZK60A (zirconium, high strength)
A zirconium-containing magnesium alloy with the highest strength of the conventional grades. It machines like a hard aluminium, and the zirconium makes the grain finer and the surface cleaner.
Quoting this material
- Typical lead time
- 18–28 working days
- Condition
- Extruded or forged, T5 aged
- Achievable finish
- Ra 1.6 µm typical · Ra 0.4 µm best
Machined in-house to your drawing: see the precision CNC machining service and the machine and inspection capability it runs on.
Machinability
Our own 1–10 shop ranking, not a published index: 10 is free-cutting brass C360, 1 is Inconel 718. It ranks how a material behaves on the floor - cycle time, chip control and tool life together. Where a published index exists it is quoted in the note.
A zirconium-containing magnesium alloy with the highest strength of the conventional grades. It machines like a hard aluminium, and the zirconium makes the grain finer and the surface cleaner.
Properties as supplied
| Parameter | Value | Unit |
|---|---|---|
| Tensile strength | 340–360 | MPa |
| Yield strength (0.2%) | 250–290 | MPa |
| Elongation | 5–11 | % |
| Hardness | 70 | HB |
| Thermal conductivity | 116 | W/m·K |
| Modulus of elasticity | 45 | GPa |
Hardness, tensile and thermal figures are typical published values for the condition stated. Actual mill certificates govern; send the specification with the drawing and we confirm against the certificate before the material is cut.
Condition
Extruded or forged, T5 aged
Heat treatment
Age hardened to develop the strength. The zirconium addition refines the grain, which is what allows the combination of strength and ductility this grade is used for.
Achievable surface finish
Ra 1.6 µm
Ra 0.4 µm
Takes a good finish; conversion coating or anodising is required for corrosion protection.
Tooling and cutting parameters
Cutting speed
- 300–600 m/min (sharp uncoated carbide)
Feed
- 0.10–0.30 mm/rev turning · 0.10–0.25 mm/tooth milling
Tooling
- Sharp uncoated carbide with large clearance
Coolant
- Mineral-oil mist or dry
Starting points for carbide on a rigid setup, not a guarantee. The right numbers depend on the machine, the toolholder and the fixturing - ask and we will say what we would actually run.
Typical applications
- Aerospace structural components
- Helicopter and rotorcraft parts
- High-strength forged fittings
- Motorsport and racing hardware
- Military equipment components
DFM notes for this grade
- Higher strength than AZ80 at a slightly higher cost and with less availability - specify it when the strength is genuinely needed
- Zirconium-containing grades are sensitive to the iron and nickel content: the corrosion behaviour depends on the melt quality, so the mill certificate matters
- Same modulus as the other magnesium grades: 45 GPa, so stiffness is still the design limit and the section has to be deeper than an aluminium equivalent
Questions buyers ask
- Why is ZK60A used in aerospace?
- It is the strongest of the conventional wrought magnesium alloys at around 350 MPa, so for a part where every gram matters and the load is real, it is the material that closes the gap. Helicopter and rotorcraft structural parts are the classic application.
- Why is zirconium added to a magnesium alloy?
- Grain refinement. A finer grain gives a better combination of strength and ductility in a wrought product, and it also improves the casting quality in the grades that use it. It is a metallurgical addition rather than a corrosion one.
Grades we would quote instead
AZ80A
8/10A wrought magnesium alloy with the highest strength of the common AZ grades: it machines like a harder aluminium and holds a better finished surface than the casting grades.
AZ31B
9/10Magnesium machines faster than aluminium with a sharper finish, provided the chip is kept moving and the swarf rules are respected.
Elektron 21
6/10A rare-earth magnesium alloy for high-temperature service: around 200 °C where the conventional AZ and AM grades have long since crept.