zinc aluminum is the more common die casting alloy and can be used in a variety of applications. It is stronger than aluminum and is more compatible with surface finishing options including plating, powder coating and painting.
Its superior oxidation-resistance grants two to four times the life span of traditional galvanized metal, making it an ideal choice for many applications that are not exposed to salt water. It is also cost effective, since the application process uses only hot dip instead of the more expensive continuous galvanizing process. It offers the formability and galvanic protection of zinc coatings, but can be welded just like aluminum and is a stronger alloy than steel.
Both aluminized iron and galvanized steel are susceptible to corrosion from exposure to salt water, but zinc aluminum is more resistant, providing protection that lasts for a long time. It can replace less demanding stainless steels in certain applications, as it is not sensitive to pitting and crevice corrosion and carries a good load capacity.
The development of low-melting-point high-aluminum-zinc alloys that can be used for gravity casting is a challenge in the field of foundry engineering (Ref 27). A novel Zn-Ti master alloy allows the melted alloy to be inoculated at a temperature much lower than the 740 degC required by the use of Al-Ti master alloys. The addition of the Zn-Ti master alloy leads to structural refinement of the a(Al) matrix by enhancing the formation of the metastable e-CuZn4 phase, which is able to nucleate fcc Al dendrites and hcp Zn lamellae in the a(Al) solid solution. This unique lamellar structure can be clearly visualized by scanning electron microscopy backscattered and energy-dispersive X-ray spectroscopy elemental mappings (Supplementary Fig. 4).