A new material with a higher melting point than any other known substance has been invented by scientists.
The exotic alloy, which is a combination of the rare metal hafnium, carbon and nitrogen, would only begin to melt into a liquid at temperatures of more than 4,126°C (7,460°F) – two thirds the temperature of the surface of the sun.
The extreme melting point makes the metal a candidate for creating a real-life version of adamantium – the almost indestructible fictional metal used to make Wolverine’s claws in the X-Men comics.
Scientists develop the new material using computer simulations to calculate the optimal composition that would give the material its record breaking melting point.
The researchers are now hoping to synthesise the material and to test its properties in the laboratory.
Professor Axel van de Walle, an engineer at Brown University, Rhode Island, who led the research, said: ‘The advantage of starting with the computational approach is we can try lots of different combinations very cheaply and find ones that might be worth experimenting with in the lab.
‘Otherwise we’d just be shooting in the dark. Now we know we have something that’s worth a try.’
Until the scientists have successfully synthesised the new alloy and tested its melting point, the record for highest melting point will remain with a substance made using hafnium, tantalum and carbon (Hf-N-C), which melts at a temperature 3,526°C.
The researchers calculated the formula for the new alloy (Hf-N-C) by simulating the physical processes that occur at the atomic level when a substance melts.
They started by analysing the properties of the Hf-Ta-C material and then looked for compounds that might maximise those further.
They found Hf-Ta-C combined a high heat of fusion – the energy absorbed or released when it transforms from solid to liquid – and low differences in disorder of the atoms, or entropy, as a solid or liquid.
Most metals require high temperatures to melt because they have stable molecular structures that require a lot of energy to break. The behaviour of the atoms as a liquid also determines this melting point.
They found their Hf-N-C alloy would absorb similar amounts of energy when it melted but had a smaller difference between the in the entropy between a solid and liquid.
They worked out its melting point would be 474°C higher than Hf-Ta-C.
Professor van de Walle and Dr Qijun Hong, who also took part in the research, say their research could help develop new types of heat shields on spacecraft or be used in gas turbines.
owever, they caution that the exact uses of Hf-N-C will be unclear until they can test its other properties. They are working with researchers at the University of California, Davis, to synthesise the compound.
Professor van de Walle added: Melting point isn’t the only property that’s important [in material applications.
‘You would need to consider things like mechanical properties and oxidation resistance and all sorts of other properties.
‘So taking those things into account you may want to mix other things with this that might lower the melting point.
‘But since you’re already starting so high, you have more leeway to adjust other properties. So I think this gives people an idea of what can be done.’