A £4.7 million UK research campaign aimed at developing lighter and more capable materials for future aero engines is being spearheaded by Rolls-Royce.
Called the ADvanced Aeroengine Materials (ADAM) programme, it is a collaboration between Rolls-Royce and QinetiQ, together with several UK academic centres of excellence, co-funded by the UK Department of Trade and industry, the Engineering and Physical Sciences Research Council (EPSRC) and the Ministry of Defence (MoD).
Within the ADAM programme, five projects will focus on high-temperature turbine materials, lightweight magnetic and electrical technologies, advanced composites, advanced joining techniques and innovative powder material processes. These novel technologies will be delivered in a four-year timeframe, and the target date for first use in a demonstrator could be as early as 2008.
Rolls-Royce already works closely with several universities and research bodies in the area of materials, and for ADAM will collaborate with the universities of Birmingham, Cambridge, Cranfield, Manchester, Oxford, and Wales (Swansea), together with the Oxford-based Faraday Advance and QinetiQ
ADAM is one of nine Defence and Aerospace Research Partnership (DARP) projects. The DARP programme is managed by the National Defence and Aerosystems Panel Research and Technology task force, bringing together the DTI, EPSRC, MoD and industry to agree and fund suitable projects. The DARP centred on materials for aeroengines was put together by Rolls-Royce, submitted a year ago and went live on 19 April.
The academic partners will play a key role in providing a detailed scientific understanding, while Rolls-Royce will take the technical lead and act as programme manager. It will also ensure that results are delivered on time and are disseminated across the UK’s industrial and academic base, thereby creating a virtual centre of excellence for the future development of gas turbine materials.
The DARP project will also provide an established group of researchers working in a well defined field that can link in actively with other materials-related initiatives, further ensuring a coherent UK approach to materials development.
Five packages within ADAM have been launched and all of them will span the next four years. They are:
• Joining will look at the friction welding of dissimilar nickel materials, for disk and blade applications. This will support work already carried out on inertia welding to manufacture real components. According to Colin Small, Project Manager, External Research (Materials) at Rolls-Royce, ‘The challenge is that you’ve got a relatively weak piece of nickel and a very strong piece of nickel with very different properties.’
• The development of a fourth generation single crystal alloy will have particular importance for the first set of blades in a turbine, as these define what the rest of the engine can do. ‘Our current material is CMSX 4, which is a second generation material, but we’re looking to develop something that will run 50°C hotter,’ says Small. ‘We’re not just developing the base material – we’re trying to develop the whole blade alloy system. As well as developing the base material, we are also studying interactions with bond-coat, the top thermal barrier layer and how these elements can be ‘life’d’. We are attempting to develop a full system, not just one or two parts of it,’ continued Small.
• Innovative powder materials will examine HIPping with titanium powder. Rolls-Royce thinks that there is sufficient technology to go very close to full density near net shape HIPping for very large components. (HIPping is short for Hot Isostatic Processing and involves the simultaneous application of high-temperature and high gas (typically inert) pressure to a workpiece in a specially constructed pressure vessel). The company is looking to produce full engine diameter components, some two or three feet across. At the moment these are machined from solid, which takes a long time, is not very environmentally friendly and results in a component that is heavier than it needs to be because of the limitations of machining. According to Small, ‘We think that by using Russian technology we can manufacture engine components near net shape, which will allow us to optimise the design, reduce the environmental impact and do it cheaper. Initially we will work in titanium, but if successful there are plans to use all sorts of materials.’
• The fourth programme will look at the next generation of metal matrix composites - silicon carbide reinforced titanium type materials. Rolls-Royce is a world leader in this area at the moment with the engine programmes for the joint strike fighter, but the company is looking at higher temperature capabilities to extend composite’s use further.
• The final research programme is very speculative and is a long-term project - developing materials for a more electric engine. The idea is to replace actuators, oil, hydraulic and other similar engine systems with embedded electrical machines. This will require specialist magnetic materials. ‘The problem is the vibration and temperature that they will be exposed to in the engine core,’ says Small. ‘So we’re starting to examine the materials that will underpin the use of magnetic materials in that environment, in particular looking at insulators, conductors, soft magnetic materials and ways of improving capacitor performance in the engine environment.’
All these technologies are targeted at the next generation of engines currently under development. ‘We aim to have the single crystal material in service by 2008,’ says Small. ‘Overall, I think that ADAM is the single biggest materials programme in the UK,’ he concluded.