Do you know about zinc alloys?（2.Composition of Zinc Alloys）

In the previous chapter, we mentioned the performance basis for the wide application of zinc alloys, advantages and disadvantages.?

So, think about it, what are the constituent elements of zinc alloys? Maybe this explains the rationale for the widespread use of zinc alloys.

Let's first understand the composition of the alloy：

Its clearly that in the alloy composition effective alloying elements: aluminum, copper, magnesium; impurity elements: lead, cadmium, tin, iron.

And the role of elements in alloys:

(1) Aluminum

Effect:

① Improve casting properties, increase fluidity, refine grains, cause solid solution strengthening, and improve mechanical properties.

② Reduce the reaction ability of zinc to iron, reduce the erosion of iron materials (gooseneck, mold, crucible).

Usually the aluminum content is 3.8 to 4.3%. The main consideration is strength and fluidity, because good fluidity is a necessary condition to make the casting complete, dimensionally accurate, and smooth surface.

(2) Copper

Effect:

1. Increase the hardness and strength of the alloy;

2. Improve the wear resistance of the alloy;

3. Reduce intergranular corrosion.

Insufficient:

1. When the copper content exceeds 1.25%, the die casting size and mechanical strength will change with time

2. Reduce the ductility of the alloy

(3) Magnesium

Effect:

① Reduce intergranular corrosion

② Refine the alloy structure and increase the strength

③ Enhance the wear resistance of alloys

Insufficient:

① When the magnesium content is > 0.08%, hot brittleness, decreased toughness, and decreased fluidity will occur

② It is easy to oxidize and lose in the molten state of the alloy

(3) Impurity elements: mainly include lead, cadmium, tin.

Influence: The intergranular corrosion of zinc alloy becomes very sensitive, which accelerates its own intergranular corrosion in warm and humid environments, reduces mechanical properties, and causes dimensional changes in castings.

When the content of impurity elements lead and cadmium in the zinc alloy is too high, the surface quality of the workpiece is normal when it is just die-casting, but after being stored at room temperature for a period of time (2~6 months), the surface appears bubbling, and the product is damaged.

(4) Impurity element: Iron

① Iron and aluminum react to form Al5Fe2 intermetallic compounds, resulting in the loss of aluminum and the formation of scum.

② Hard spots are formed in the die casting, which affects post-processing and polishing.

③ Make zinc alloy products brittle.

Based on the above elements, zinc alloys are broadly divided into three categories:

Binary, ternary, and multicomponent alloys.

(It is worth noting that zinc-based alloys, zinc alloys, and zinc-aluminum alloys are all broad concepts, not referring to the concept that the alloy can meet a specific function.

For example, zinc-aluminum alloys are divided into low-aluminum-zinc-based alloys, medium-aluminum-zinc-based alloys and high-aluminum-zinc-based alloys according to the aluminum content. Although they are all zinc-aluminum alloys, their properties are quite different. )

Low-aluminum-zinc-based alloys are generally binary alloys. Mainly used for anti-corrosion function, basically replace the galvanized process (new technology) with sprayed galvanized aluminum alloy.

Medium-aluminum-zinc-based alloys are generally ternary alloys. Mainly used for fastening function, with good construction convenience.

High-aluminum zinc-based alloys are generally ternary or multi-component alloys, which are called "magic alloys", because of their superior properties, they can be applied in various directions according to different changes in a single property.

Are you also curious, are there any special requirements for zinc alloys that can be used for custom wine stoppers, ornaments, artworks, etc.?

See you in the next chapter.

For custom zinc alloy accessories, contact Tracy: