Magnesium Alloys 101: Know Your Alloys

Magnesium alloys are well-known for being the lightest structural alloys available in the market for product light-weighting for performance-intensive industries like Automotive, Biomedical, Aerospace, Defence, Consumer Electronics, Commercial Sectors, Industrial Machinery, and Aviation.

Some of the desirable properties of Magnesium include low specific gravity, excellent EMI/EMC properties, very high damping/shock resistance, and high strength to weight ratio. As a result, new Magnesium Alloys available in India are able to replace Aluminium, Steel, Plastics, and even Carbon Fibre for cost-effective performance improvement.

Types and designation

It is possible to categorize Magnesium alloys into two groups:

• Cast Alloys

• Wrought Alloys

Cast alloys are made by pouring the molten liquid metal into a mold, through which it solidifies into the shape necessary. Popular Magnesium cast alloys consist of varying quantities of Aluminum, Manganese, and Zinc as primary alloying elements, but not exceeding 10%. Other alloying materials, such as zirconium and rare-earth metals, have also been used recently, mainly to increase creep resistance. Besides, heat treatments improve the mechanical properties of cast alloys.

Wrought alloys are alloys subjected to mechanical work to achieve the desired form, such as forging, extrusion, and rolling operations. The major alloying elements are also Aluminum, Manganese, and Zinc. Magnesium wrought alloys are sorted into alloys that are heat treatable and non-heat-treatable.

If you wish to find out the most commonly used Magnesium Alloys in India, you can read about them here. If you wish to receive a property Datasheet of the various Magnesium Alloys which we can manufacture, you can send us an email request here.

Designation schemes displaying the alloying elements and their relative details have been developed to understand the compositions of the alloys. The ASTM Standard Alloy Designation System is one of the most commonly used designation systems. It consists of four pieces, defined in the example below:

Example: AZ91E-T6

1. The first component (AZ): the two primary alloying elements are named in the order of their composition percentage weightage in the Magnesium Alloy. In this case, “A” stands for Aluminium and “Z” stands for Zinc.

2. The second part (91): defines the percentage quantity of the principal alloying components (Aluminium at 9% and Zinc at 1%, respectively)

3. The third part (E): distinguishes alloys having the same quantities of the main alloying components (a fifth standardized alloy with the above percentages)

4. The fourth component (T6): specifies the alloy temper condition, which in this case is T6.

So, Magnesium alloys are named and grouped using their main alloying elements in the ASTM designation scheme. You can identify the alloy composition in any Magnesium Alloy using the table below:

A -AluminumB -BismuthC -CopperD -CadmiumE -Rare EarthF -IronG -MagnesiumH -ThoriumJ -StrontiumK -ZirconiumL -LithiumM -ManganeseN -NickelP -LeadQ -SilverR -ChromiumS -SiliconT -TinY -AntimonyZ -Zinc

If you wish to find out the most commonly used Magnesium Alloys in India, you can read about them here. If you wish to receive a property Datasheet of the various Magnesium Alloys which we can manufacture, you can send us an email request here.

Physical characteristics

Due to their high strength-to-weight ratios, excellent machinability, and low cost, Magnesium alloys are materials of interest. Compared with other typical alloys, such as aluminum or steel alloys, they have a low specific gravity of 1.74 g/cm3 and a relatively low Young's modulus (42 GPa). At room temperature, however, they suffer from brittleness.

Magnesium alloys are the third most commonly used structural metal for casting internationally. Based on their chemical compositions, the physical properties of the alloys change. Adding different alloying elements can, under different conditions, result in different properties.

• Aluminum increases strength, hardness, and ductility, making the casting process of the alloy simpler.

• Zinc increases the power of room-temperature, casting fluidity, and corrosion resistance.

• By forming intermetallic compounds with iron-like metals to be eliminated during melting, manganese increases the resistance of AM and AZ alloys to saltwater corrosion.

• Rare earth metals help to improve strength and resistance to creep and corrosion at high temperatures and reduce porosity and weld cracking.

• When applied to alloys containing zinc and rare earth metals, zirconium is a good grain refiner.

• During casting and welding, beryllium helps minimize surface oxidation.

Applications

From automotive and aerospace applications to electronic and biomedical uses, Magnesium alloys cover a wide variety of applications.

Applications in structure

Examples of structural applications include automobile, aerospace, industrial, and commercial applications. Lightweight, high strength-to-weight ratio, high rigidity-to-weight ratio, castability, machinability, and great damping are the advantages of Magnesium alloys to be used in such applications.

• Automotive: brake and clutch support brackets, transmission housing

• Aerospace: landing wheels, fittings for the helicopter rotor, gearbox housing

• Industrial: high-speed machinery for working, such as sewing machines

• Business: baggage, hand tools, computer cases, ladders

Applications electronically

Electronic applications include electronic packaging, arms for hard drives, mobile phones, and enclosures for portable media devices. Due to their lightweight, strength, and toughness, Magnesium alloys are used instead of plastics. They are also relatively stronger in terms of heat dissipation and protection against interference with electromagnetic and radio frequencies.

Applications in medicine

Magnesium alloys make good use of portable medical equipment and wheelchairs that require light materials. Cardiovascular stents and orthopedic appliances are also possible applications of some Magnesium alloys due to the biocompatibility and bio absorbability of Magnesium.