Zinc aluminium

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Zinc-aluminium alloys, more commonly referred to as ZA, are named as such because the main constituents are zinc and aluminium. Other alloying elements include magnesium and copper. This type of alloy was originally developed for gravity casting. Noranda, New Jersey Zinc Co. Ltd., St. Joe Mineral Co. and ILZRO were the main companies that pioneered the ZA alloys between the 1950s and the 1970s. They were designed to compete with bronze, cast iron and aluminium using sand and permanent mold casting methods. Distinguishing features of ZA alloys include high as-cast strength, excellent bearing properties, as well as low energy requirements (for melting).[1]

The numbers associated with the name represent the amount of aluminium in the alloy (i.e. ZA8 has 8% aluminium).[1]


[edit] Mechanical properties

[1] ZA6 ZA12 ZA27
Mechanical Properties Sand Cast Permanent Mold Sand Cast Permanent Mold Sand Cast Permanent Mold
Ultimate Tensile Strength [psi x 103 (MPa)] 38 (263) 32-37 (221-255) 40-46 (276-317) 45-50 (310-345) 58-64 (400-441) 45-47 (310-324)
Yield Strength - 0.2% Offset [psi x 103 (MPa)] 29 (200) 30 (206) 31 (214) 39 (269) 54 (372) 37 (255)
Elongation [% in 2"] 1-2 1-2 1-3 1-3 3-6 8-11
Shear Strength [psi x 103 (MPa)] - 35 (241) 37 (255) - 42 (290) 33 (228)
Hardness [Brinell] 85 85-90 89-105 89-105 110-120 90-110
Impact Strength [ft·lbf (J)] 156 (20) - 193 (25) - 353 (47) 433 (58)
Fatigue Strength Rotary Bend [5x108 cycles: psi x 103 (MPa)] - 7.5 (52) 15 (103) - 25 (172) 15 (103)
Compressive Yield Strength 0.1% Offset [psi x 103 (MPa)] 29 (199) 31 (214) 33 (227) 34 (234) 48 (331) 37 (255)
Modulus of Elasticity [psi x 106 (MPa x 103)] 12.4 (85.5) 12.47 (85.5) 12.07 (82.7) 12.07 (82.7) 11.37 (77.9) 11.37 (77.9)
Poisson's Ratio 0.29 0.29 0.30 0.30 0.32 0.32

[edit] References

  1. ^ a b c Gravity Casting Alloys. Eastern Alloys, Inc.. Retrieved on 2007-07-19.

[edit] See also