Novel Bainite at the Science Museum, London, July 2006

H. K. D. H. Bhadeshia

A new exhibit at the Science Museum, describing a novel steel which has crystals of bainitic ferrite which are embedded in an austenitic matrix. The crystals have a controlling scale which is finer than that of carbon nanotubes. And yet, the steel is cheap, can be made large in all of its three dimensions, and does not require deformation or severe heat-treatment to reveal its huge strength and other desirable properties such as toughness.

100 years

The theory that was used to create the alloy has also predicted that in another steel, the crystalline state will change into bainite in about 100 years at room temperature. Two samples of this second steel were made two years ago, one of which can be seen at the exhibit with the other one archived at Cambridge University. The surface of the sample can be observed, and will change from a mirror finish to displacements characteristic of the phase change. The samples are sealed in an inert atmosphere within quartz tubes which should be stable over the required time period (illustrated in the moving pictures icon below).

Dr Susan Mossman and Mike Cronkshaw of the Science Museum converted the results into the exhibit. The huge coloured picture shows the structure of the novel steel, the width of each individual crystal being of the order of 20 nm. There are publications available describing the original work, which also contain the names of the inventors.