ZK60A

ZK60A is a wrought magnesium base alloy containing zinc and zirconium. Increased strength is obtained by artificial aging from the as-fabricated form. ZK60A-T5 has the best combination of strength and ductility at room-temperature of the wrought magnesium alloys.

APPLICATIONS

Forgings and extrusions in ZK60A find application in high strength parts for use primarily where the service temperature is below 150°C. ZK60A forgings can be used where pressure tightness or machinability are required. That parts are dimensionally stable during and after machining is also an important design consideration.

Forgings and extrusions in ZK60A find application in high strength parts for satellites, helicopter gearboxes and rotor hubs, bicycle frames, roadwheels, missle frames and interstage fairings, brake housings and landing gear struts.

SPECIFICATIONS

ASTM B91

ASTM B107/B107M-13

CHEMICAL COMPOSITION

Zinc 4.8-6.2%

Zirconium 0.45% min

Magnesium Balance

Dimension Scope

Forgings: Max. length 1000mm, max. width 500mm, max thickness 330mm.

Extrusions: Diameter 6mm - 180mm for round bar; thickness and width 10-220mm for square/rectangular section. Length: 100mm - 6000mm

Thickness and width are inter-dependant.

HEAT TREATMENT

As-fabricated (F) forgings can be converted to the precipitation treated temper (T5) by heating to 150°C for 24 hours, followed by air cooling.

PHYSICAL PROPERTIES

Specific Gravity 1.83

Coefficient of Thermal Expansion 27.1x10 -6 K -1

Thermal Conductivity 121 Wm -1 K -1

Specific Heat 1100 Jkg -1 K -1

Electrical Resistivity 57 nΩm

Modulus of Elasticity 45GPa

Poissons Ratio 0.35

Melting Range 520-635°C

TYPICAL HARDNESS

ZK60A-T6 85 Rockwell E

ZK60A-T5 77 Rockwell E

WELDABILITY

ZK60A is not considered to be weldable by conventional techniques due to hot-shortness cracking. However, resistance welding response is excellent. Friction stir welding can be used to join ZK60A to itself and other magnesium alloys.

MACHINING

ZK60A, like all magnesium alloy forgings, machines 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 centimeter of metal removed varies from 9 to 14 watts per minute depending on the operation.

SURFACE TREATMENT

All the normal chromating, anodizing, plating, and finishing treatments are readily applicable.