Zincaluminium

Zinc-aluminium, commonly referred to as ZA alloys, are a family of zinc-based die-casting alloys in which aluminium serves as the principal alloying element. The most widely used grades are ZA-8, ZA-12, and ZA-27, named for approximately 8%, 12%, and 27% aluminium by weight. The balance is zinc, with small additions of other elements sometimes included to tailor properties.

ZA alloys offer higher strength and hardness than conventional zinc alloys, while maintaining excellent castability and good wear resistance. They also exhibit improved dimensional stability during cooling and reduced shrinkage compared with some other zinc alloys, making them well suited for complex, close-tolerance parts. The relatively high aluminium content raises the melting point and affects fluidity; as a result, ZA alloys require precision control of temperature and gating in high-pressure die casting.

Common applications include automotive and appliance components, housings for electrical equipment, gears, and precision fittings where a combination of strength, stiffness, and intricate geometry is needed. They are typically produced by high-pressure die casting and are used in as-cast form or with limited post-processing.

Limitations include sensitivity to corrosive environments compared with aluminum alloys, and higher cost relative to simpler zinc alloys. Machinability remains good, and heat-treatability is limited, so performance gains are mainly achieved through alloy composition and casting design.

ZA alloys were developed in the mid-20th century to combine the light weight and ease of casting of zinc with higher mechanical properties, and they remain in use for small to medium-sized die-cast parts requiring precision and durability.