Alloy 7 is a modification of Alloy 3. It is a high-purity alloy containing lower magnesium content and has a tighter impurities specification. This results in improved casting fluidity, ductility and surface finish. Most alloy 7 is used for special hardware applications, or when castings require extra formability during subsequent assembly operations such as crimping or staking. The higher fluidity also allows thinner walls to be cast.
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Alloy 7 is a modification of Alloy 3. It is a high-purity alloy containing lower magnesium content and has a tighter impurities specification. This results in improved casting fluidity, ductility and surface finish. Most alloy 7 is used for special hardware applications, or when castings require extra formability during subsequent assembly operations such as crimping or staking. The higher fluidity also allows thinner walls to be cast.

Higher fluidity is sometimes desirable especially on components with intricate detail, however it does present special casting considerations. In order to avoid excessive flashing along the tool parting lines, good die fit and close control of casting process parameters is necessary. The high ductility exhibited by this alloy also has an impact on processing, but mainly in secondary operations for flash removal and trimming.

The behaviour of zinc alloys under stress is non-linear and time-temperature dependent on strain-rate, i.e. the ratio of stress to strain is not constant, even at low stresses, and varies with time resulting in continuous plastic flow under constant applied load. Designers of structural components should be aware of the creep limitations of zinc alloys, which do not have a single value for elastic modulus. Yield strength (allowable stress) under sustained loading is dependent on the allowable design strain (% elongation) over the required service life. Working values for the elastic modulus and yield strength are important for design purposes.

This alloy exhibits excellent damping capacity and vibration attenuation in comparison with aluminium diecasting alloys.