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School of Materials

Strong and lightweight alloys for transportation and medical implants

It is 35% lighter than aluminium and 80% lighter than steel; magnesium seems like the perfect metal when weight really matters. But traditional magnesium alloys are weak, they corrode easily and degrade at high temperatures. By adding specific rare-earth elements into the mix, research at The University of Manchester led to development of a new class of high performance, low density magnesium alloys.

Made today by Magnesium Elektron (ME), the international leader in magnesium alloys, these alloys are today helping aerospace and automotive manufacturers to increase product performance and reduce fuel consumption of aircraft and motor vehicles.

Despite the attractiveness of magnesium as a lightweight structural metal, the use of traditional magnesium alloys has been limited in industry because they have serious shortcomings: poor strength, poor corrosion resistance, and a limited capacity for temperature increases.

Research at The University of Manchester found how to overcome these limitations and meet the stringent performance specifications for aerospace, automotive, and military applications. The researchers developed a new family of high-performance magnesium alloys with greater strength and better corrosion performance than any commercial magnesium alloy then available on the market.

Usage icon

Usage

Used in military aircraft, motor vehicles and medical devices.

35 per cent lighter icon

Lighter aircrafts

Aircraft components 35% lighter.

10 per cent fewer CO2 emissions icon

Emissions

Aircraft fuel use and emissions cut by 10%.

Despite the attractiveness of magnesium as a lightweight structural metal, the use of traditional magnesium alloys has been limited in industry because they have serious shortcomings: poor strength, poor corrosion resistance, and a limited capacity for temperature increases.

Research at The University of Manchester found how to overcome these limitations and meet the stringent performance specifications for aerospace, automotive, and military applications. The researchers developed a new family of high-performance magnesium alloys with greater strength and better corrosion performance than any commercial magnesium alloy then available on the market.

This development is the culmination of 20 years of collaboration between the University and Magnesium Elektron, a global specialist in magnesium materials and technologies. During this time researchers have contributed to significant improvements in commercial magnesium alloy performance and this latest specialist alloy is the best yet. Its exceptional properties have enabled Magnesium Elektron to sell to customers in the aerospace, automotive and medical markets.

Today the new alloys and associated corrosion protection systems are used extensively in helicopter and fixed wing military aircraft, including the Westland Lynx, McDonnell Douglas MD500, F22 Raptor and Apache Mark-3 attack helicopter and the F35 Joint Strike Fighter (JSF). Replacing aluminium, the alloys give a 35% mass reduction so the aircraft meet critical performance and range targets. These aircraft are being manufactured in large numbers; approximately 3,100 F35 JSF aircraft are expected to be in service by 2035.

Two new alloy products are currently undergoing final certification for civil aerospace; they will be used for components in Airbus and Boeing aeroplanes and could result in a 10% reduction in fuel consumption and emissions.

These new alloys are also finding their way into motorsports and biomedicine. In wheels, gearboxes and engines, the alloy improves the strength-to-weight ratio of vehicles by 20-25% and can make a racing car up to 10kg lighter, with better acceleration and braking performance. A specific alloy, called Synermag, has also been patented for use in bioresorbable stents, wire, and screws. These products have already passed animal trials and are now being certified for surgical use in humans. Synermag is produced in a dedicated $2 million facility in the UK.

Background

10kg lighter icon

Lighter vehicles

Vehicles up to 10kg lighter, with better acceleration and braking.

25 per cent stronger icon

Strength

Motor vehicle strength-to-weight ratio increased by 20-25%.

Over the course of 20 years researchers at The University of Manchester have studied how the microstructure of magnesium alloys affects performance. The team has elucidated the complex relationships between microstructure, the properties of the material and its processing conditions.

Based on these studies the researchers have been able to identify new additives and processing conditions that produce new alloys with exceptional properties. In particular, the team discovered how rare-earth elements in the mix could strengthen magnesium alloys beyond anything previously observed, thanks to the combination of precipitated nanoparticles and a unique crystallographic texture.

In parallel to the microstructural analyses and performance testing, the team also developed novel protection systems to permit the new alloys to be used in demanding structural applications and aggressive environments (eg: seawater) that were previously impossible. These included environmentally-friendly corrosion protection methods that replace previous harmful technologies.

The team

Lead academics:

Post Doctorial Research Associates:

  • R Cottam
  • E Matykina

PhD students:

  • MA Gonzalez-Nunez
  • P Apps
  • A Twier
  • R Arrubal

EngD student:

  • R Thornton

List of references

  • P. J. Apps, H. Karimzadeh, J. F. King, G. W. Lorimer, Precipitation reactions in magnesium-rare earth alloys containing yttrium, gadolinium or dysprosium, Scripta Materialia, 48, 2003, 1023-1028. (170 citations to date, source Google Scholar)
  • M. A. Gonzalez-Nunez, C. A. Nunez-Lopez, P. Skeldon, G. E. Thompson, H. Karimzadeh, P. Lyon, T. E. Wilks, A non-chromate conversion coating for magnesium alloys and magnesium-based metal matrix composites, Corrosion Science, Volume 37, Issue 11, November 1995, Pages 1763-1772. (136 citations to date, source Google Scholar)
  • R. Cottam, J. Robson, G. Lorimer, B. Davis, Dynamic recrystallization of Mg and Mg-Y alloys: Crystallographic texture development, Materials Science and Engineering: A, Volume 485, Issues 1-2, 25 June 2008, Pages 375-382. (81 citations to date, source Google Scholar)