At any one time over half a million people are flying far above our heads in modern aircraft. Their lives depend on the performance of the special metals used inside jet engines, where temperatures can reach over 2000˚C. Cambridge researchers will be exhibiting these remarkable materials at this year’s Royal Society Summer Science Exhibition.
At any one time over half a million people are flying far above our heads in modern aircraft. Their lives depend on the performance of the special metals used inside jet engines, where temperatures can reach over 2000˚C. Cambridge researchers will be exhibiting these remarkable materials at this year’s Royal Society Summer Science Exhibition.
In jet engines, we currently use special metals called superalloys that exhibit exceptional high-temperature mechanical properties and resistance to corrosion
Cathie Rae
The ever-increasing demand for air travel while simultaneously reducing carbon emissions constitutes a huge engineering challenge. Greater efficiency requires engines to run hotter and faster, but today’s best materials are already running close to their limits.
The metals inside a jet engine must operate in a gas stream about a third as hot as the sun’s surface while enduring centrifugal forces equivalent to hanging a double-decker bus from each turbine blade.
At the University of Cambridge, researchers are designing new alloys that are able to withstand even more extreme conditions of stress and temperature, as Dr Cathie Rae at the Cambridge Rolls-Royce University Technology Centre (UTC) explains: “In jet engines, we currently use special metals called superalloys that are created by mixing together nickel with other elements.
“They are called superalloys because they exhibit exceptional high-temperature mechanical properties and resistance to corrosion. In fact, they actually get stronger as we heat them up. We’re trying to make materials that are even better than these superalloys!”
Visitors to the Engineering Atoms exhibit at the Royal Society Summer Science Exhibition from 30 June until 5 July will be able to see how the atomic structure of materials affects their properties, and will be able to handle real jet engine components.
In the Rolls-Royce UTC, scientists work in close collaboration with one of the world’s leading engine manufacturers, Rolls-Royce plc, and the Engineering and Physical Sciences Research Council (EPSRC) to design and make new high-temperature materials. To achieve this, they need to understand everything from the shape and design of the component right down to the behaviour of individual atoms in the metal. By engineering the arrangement of the atoms, varying their type, position and size, researchers can radically change how these metals perform.
This involves the use of powerful microscopes that use electrons instead of optical light to examine materials on the atomic scale. By using these electron microscopes, researchers can look at individual rows of atoms and identify their composition. The Engineering Atoms stand will have a working scanning electron microscope, the Phenom ProX, so visitors will be able to look at alloys on the micrometre scale.
Engineering Atoms will also be exhibiting amazing materials that ‘remember’ their original shape after they’ve been deformed. These ‘shape-memory’ alloys, made from titanium and nickel, can be used to control and optimise airflow in jet engines where conventional hydraulic or electrical control systems would be difficult to operate.
The Summer Science Exhibition will be open to the public from 30 June to 5 July 2015.
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