The British Ministry of Defence (MoD) announced late last month that its Defence Science and Technology Laboratory (officially abbreviated to Dstl) had, in cooperation with the University of Sheffield, developed a radical new method of producing titanium parts. The Dstl has so far invested almost £30 000 in this research and development programme. Titanium combines high strength and corrosion resistance with low weight. It is as strong as steel but is only 50% of the weight of steel. But it is some ten times more expensive than steel and it is difficult and expensive to make titanium products.
The new technology is called FAST-forge and cuts the number of steps required to manufacture titanium parts from 40 to just 2. The technology has been proved at laboratory scale and a pilot plant (described by the UK MoD as “large-scale”) has been completed and will soon start operation. The pilot plant has been jointly funded by the Dstl and the UK subsidiary of US group Kennametal Manufacturing.
“FAST-forge is a disruptive technology that enables near-net-shape components to be produced from powder or particulate in two simple processing steps,” explained University of Sheffield (Sheffield Titanium Research Group) researcher Dr Nick Weston. “Such components have mechanical properties equivalent to forged product. For titanium alloys, FAST-forge will provide a step change in the cost of components, allowing use in automotive applications such as powertrain and suspension systems.”
“We’re really excited about this innovation, which could cut the production cost of titanium parts by up to 50%,” highlighted Dstl materials science principal scientist Matthew Lunt. “With this reduction in cost, we could use titanium in submarines, where corrosion resistance would extend the life, or for light-weight requirements like armoured vehicles.”
“Our Armed Forces use titanium in everything from cutting-edge nuclear submarines and fighter jets through to life-changing replacement limbs – but production time and costs mean we haven’t always used it,” stated UK Defence Secretary (Minister) Gavin Williamson. “This ground-braking method is not only faster and cheaper but could see a huge expansion [in the range] of titanium parts and equipment throughout the military. It is a clear example of how our world-class scientists are working behind the scenes to help our Armed Forces as well as bringing prosperity and security to Britain.”
FAST-forge is part of a wider programme to cut the costs of producing titanium parts and increasing their use, especially in the aerospace industry. Other partners in this wider programme are UK company Metalysis, the Advanced Forming Research Centre (AFRC – based at the University of Strathclyde, in Glasgow) and French aircraft undercarriage manufacturer Safran Landing Systems. Innovate UK, the national innovation funding agency, has also helped finance the programme.
The overall programme currently has three ‘steps’, or phases, the FAST-forge itself being Step 2. While the FAST-forge uses titanium powder, Step 1 was focused on producing that powder. The research for Step 1 was conducted in partnership with Metalysis and has resulted in the development of a “low-cost one solid- state extraction process, as opposed to the current multistep method, for high-strength titanium alloy powder [by] using field- assisted sintering technology”, in the words of Sheffield University’s Department of Materials Science and Engineering.
It is the titanium alloy powder produced by this process that provides the feedstock for the FAST-forge developed in the second phase. FAST-forge processing itself involves two phases or steps. “The first step is to use field- assisted sintering technology to rapidly consolidate titanium powder into a shaped preform billet,” explained Weston. The second step then uses a precision hot forge to finish the preform to the required component shape and microstructure.”
Step 3, in cooperation with Safran Landing Systems, combines FAST-forge with a one-step forging process developed by AFRC and establishing how it can be incorporated into a new British supply chain and be used in the manufacture of landing gear.