Aluminum Alloys vs. Magnesium Alloys and Zinc Alloys

Different Alloy Properties
Aluminum, magnesium, zinc are the four most commonly used alloys in die casting processes in China. Your design's application, material density, tensile strength, yield strength, melting temperature and modulus of elasticity are all important factors in selecting the alloy best suited to your design needs.

Aluminum VS Magnesium Alloys
Like aluminum, magnesium alloys are utilized in the casting of automotive parts and provide their own unique mechanical and physical properties. While there have been experiments conducted to substitute magnesium for aluminum, it is still softer, less stable, more expensive and tends to bend easier when under stress.
While aluminum alloys take longer to solidify compared to magnesium alloys, its alloys provide a longer die life. In addition, aluminum does not require as much finishing work as magnesium. Special treatments and coatings are needed when determining a magnesium casting's application.
When compared to the cost of melting aluminum, new technology has lowered the expenses required to melt magnesium alloys, but casting requires a higher injection speed. Conversely, magnesium has a quicker ejection time over aluminum castings. Magnesium is also better at casting components with thinner walls and tighter tolerances than aluminum.
However, even with the many advantages of magnesium, aluminum remains a less expensive alternative for die casting.
 
Zinc VS Magnesium alloys
One of the main differences between magnesium and zinc alloys is that zinc and zinc-aluminum alloys require lower pressure and temperatures for casting. Because of a lower casting temperature, zinc provides a much longer die life than magnesium, which can help reduce production costs.
Unlike magnesium, which requires special treatments and coatings for corrosion resistance and finishing, zinc alloys also offer excellent corrosion resistance and a better surface finish when they are ejected from the die.
 
Aluminum VS Zinc Alloys
Just like with magnesium, one of the main differences between aluminum and zinc alloys is that zinc has a lower melting temperature and requires lower pressures for casting. Zinc is considered to be the most castable of all of the commonly used alloys.
By having a lower melting temperature, this enables a zinc die to last much longer than an aluminum die. Dies are expensive, and keeping them in service longer will provide a more cost-effective approach to large volume casting projects.
In addition, zinc's lower melting temperature allows for hot chamber casting, which is less expensive than cold chamber processes. By using the hot chamber die casting method, production speed will also be increased. Zinc is one of the toughest alloys around, and it surpasses even aluminum in its ability withstand impact.
Another advantage to using a zinc alloy over an aluminum one is that zinc is great for castings with very intricate details and thin walls. When utilizing zinc, very little machining, trimming or finishing work is needed as the lower pressure and melting point reduce the thermal shock it experiences during casting. When casting in zinc, it maintains a smoother surface when a component is ejected from a die.

Determining Alloy and Casting Costs
Aluminum remains the most inexpensive alloy per cubic inch of all the commonly used alloys in die casting, but market value still fluctuates. Depending on the application and size of your design, costs may be lower based on the amount of material needed and the weight of the material.
Magnesium and aluminum are lightweight materials that offer excellent stability, but they have higher melting temperatures than zinc, which can contribute to higher casting costs. Hot chamber casting, which can be utilized with zinc and magnesium alloys, is less expensive than cold chamber processes, and it can run at a faster rate.
Die manufacturing is also an expensive process, and while the costs remain steady for the actual production of the die, determining the overall expected life a die is a good way to reduce expenses. For alloys like zinc, die life lasts much longer. Magnesium's melting temperature is lower than aluminum and will allow for a longer die life as well.
When considering what alloy best suits your design needs, machining and finishing operations should also be taken into account. Zinc and zinc-aluminum alloys offer superior results over aluminum and magnesium when it comes to finishing, and they can drastically reduce the workload needed to produce a final product.
The most important thing to consider when selecting an alloy is the unique mechanical and physical properties they provide and how those will impact the performance and longevity of your design's application.
For projects involving exposure to higher temperatures, aluminum offers better strength than other alloys. For designs that require a high yield strength and modulus of elasticity, zinc alloys are the best choice. Magnesium also offers many benefits due to its lighter weight, and it can be substituted for aluminum for specific components.

To find out more about aluminum alloys and how they and other materials might work for your die casting project, contact Junying Die Casting online or by phone at 86 769 82890830.