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Materials science is considered crucial to the economic success of a country and is able to stimulate the growth of existing and new industries. Critical sectors of industry, in which materials science plays a substantial role, include aerospace, transportation, electronics, computing, telecommunications, power generation, environment and health care. In short, advances in materials science underlie all modern technologies.

A number of examples are worth highlighting. High-performance turbine blades, made from cast nickel superalloys, intermetallics and ceramics, are improving the thrust and efficiency of jet engines, making passenger flights quicker and better for the environment. Lightweight alloys - like aluminium, magnesium and titanium - are being increasingly used in car engines, thereby providing considerable weight-saving and increases in fuel-economy.

New semiconducting germanium-silicon (Ge-Si) crystals with well-controlled dopant levels are now finding applications in mobile phone circuitry. Other materials such as cadmium-telluride (CdTe) crystals are becoming more and more attractive to the medical sector, since these crystals make very good X-ray and gamma-ray detectors which can be used for dental imaging or mammography.

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It is clear that future innovations in the 21st century depend on the intelligent use of new materials. These novel materials must be researched, designed, and understood in order to meet the technical challenges facing modern industry.

Many of the industrial processes that produce materials involve at least one liquid phase. The list below highlights just a few materials processes in which a liquid component is present:

• casting (e.g. continuous-, ingot-, die-, investment- and thixo-casting),
• welding (e.g. laser-, electron beam-, gas-welding, soldering and brazing)
• semi-conductor crystal growth (e.g. Bridgman, Czochralski growth),
• advanced solidification (e.g. splat cooling, melt-spinning, atomisation, spray forming),
• metal foam production
• combustion synthesis

Because these industrial processes involve some liquid component it means that they are also radically influenced by the effects of gravity. The complex nature of these industrial processes makes it difficult to interpret experimental results on Earth. This is due to the fact that physical phenomena, such as multiphase fluid flow, diffusion, capillarity effects and heat transport, are often strongly coupled with one another and are interwoven with gravity.

Performing unique experiments in reduced gravity, like onboard the International Space Station, will allow researchers to get a much better understanding of materials productions. Microgravity can also be regarded as a useful tool for increasing the accuracy of thermophysical properties and for improving predictive models of materials processing.

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Typical questions which academic and industrial researchers ask themselves when performing materials science research include...

• what physical phenomena govern the process ?


• what influence does gravity have on the final product ?


• are there other effects that have previously been masked by gravity ?


• how can we use the acquired knowledge and data to improve industrial processes on Earth ?