Why are magnesium alloys useful in aircraft and spacecraft?

Magnesium alloys are highly valued in the aerospace industry for the construction of aircraft, rockets, and space satellites primarily due to their low density, which is only two-thirds that of aluminum. As the lightest of all machinable metals, magnesium helps reduce overall structural weight.12

Because pure magnesium lacks sufficient structural strength, it is used in the form of alloys—typically combined with aluminum, zinc, and manganese—to enhance its hardness, tensile strength, and ability to be cast, welded, and machined. These alloys are favored for their:1

• High strength-to-weight ratio: Essential for performance in flight and space travel.2
• Ease of fabrication: Magnesium is the easiest structural metal to machine, allowing for complex manufacturing operations.12
• High damping capacity: Useful for managing vibrations in structural components.2
• Dimensional stability: Alloys can be produced to close dimensional tolerances.2

While magnesium alloys are limited in cold-forming capabilities due to their hexagonal crystal structure, they are readily hot-worked and can be heat-treated to further improve their mechanical properties for specific aerospace applications.2