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The future of magnesium alloys in defence

Magnesium poses an engineering dilemma: do you opt for the lightweight, versatile light alloy at the cost of poor corrosion performance? Fortunately, new, emerging technologies are presenting new opportunities to enhance the performance of magnesium, even in applications where its lifespan would previously be considered inadequate.

In this article, we examine magnesium in the defence industry, looking at how magnesium is being increasingly used across applications as diverse as handheld equipment, to heavy vehicles and aircraft.

Optimising SWAP-C

Much is expected of materials used in defensive environments – they are required to withstand wear, corrosion, shock and friction whilst also being lightweight and affordable. Engineers must therefore carefully consider magnesium’s advantages and limitations of materials when designing defence equipment and specifying components, considering how each delivers benefits of Size, Weight, Power and Cost (SWAP-C).

Key defence vehicles and handheld equipment can all be lower in weight, longer-lasting and more cost effective when heavier steel components and housings are replaced with lighter, more flexible coated magnesium alloys. With increased use of unmanned vehicles and drones in modern defensive operations, enhanced SWAP-C performance is particularly desirable.

Components and equipment used for defence purposes clearly need to be both reliable and capable of withstanding potentially extreme and challenging conditions. Some manufacturers of defence equipment continue to use heavier materials such as steel for their products and parts. Steel is strong, durable and is resistant both to corrosion and high temperatures – all properties that can make it attractive for use in a wide range of defence projects. Perhaps the most significant negative for steel is its weight, which is why modern advances in protective technology are making magnesium alloys an attractive alternative.

Applications and considerations for magnesium alloys in defence

Magnesium alloys bring a number of benefits that are unique to certain applications across the defence sector:

  • Reducing the mass of parts by up to 50% when replacing steel, boosting both fuel efficiency and performance for aerospace and aeronautics
  • On the ground, the range of equipment required to be carried by soldiers in the field has increased to such an extent in recent years, that light weighting materials delivers obvious practical benefits to operations personnel
  • Land vehicles are built to carry huge cargo loads, and yet even when unloaded, these machines have significant weight. Specifying magnesium alloys for use in the engine (which accounts for the bulk of vehicle weight) increases fuel efficiency, range and durability and reduces the cost of maintenance. All of which combine to lower the total cost of ownership

 

Improving performance of defence equipment through PEO

Subject to all the main forms of corrosion (uniform, galvanic, pitting and filiform), untreated magnesium alloys are prone to stress erosion cracking – an undesirable trait for defence equipment. Fortunately, a cost-effective solution exists, in the form of Plasma Electrolytic Oxidation (PEO).

PEO is a bath-based technique for increasing the life and performance of light alloys, often allowing them to surpass the performance of heavier materials. Our innovative process enhances traditional anodising methods through the use of plasma, forming ceramic layers on the surface of the chosen substrate and producing materials that are strong, stable and lightweight. All key considerations for the defence industry. PEO can be used on alloys with high aluminium, magnesium and titanium content, as well as those containing zirconium, tantalum, niobium, hafnium and cobalt.

Alloys treated by PEO exhibit a number of properties which enhance the design and performance of defence equipment and components:

  • Improved resistance to multiple types of corrosion
  • Increased strength
  • Enhanced resistance to wear, friction and dry-sliding
  • Shockproof
  • Greater flexibility than steel
  • Thermal and chemical stability

PEO therefore has the potential to solve many of the challenges experienced by engineers working on projects for the defence industry, whether land, air or sea-based. By involving Keronite from a very early stage in the design process, bespoke solutions can be developed that address all key issues and deliver against specific requirements and objectives.

You can learn more about the many benefits of plasma electrolytic oxidation for magnesium alloys in the defence industry in the technical data sheet here. 

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