If a liquid metal alloy is cooled slowly it will eventually form a solid phase. Before it solidifies, however, the liquid undergoes a liquid-liquid transition to a phase in which it has the same concentration but a more strongly ordered structure. This structure has now been demonstrated for the first time by material scientists from Saarland University in a collaborative project with the German Aerospace Centre and the Leibniz Centre for Solid State and Materials Research in Dresden.
The experimental work, which was performed at the German Electron Synchrotron Facility (DESY) in Hamburg, involved levitating hot metal droplets and observing them as they cooled by irradiating them with x-rays from one of the world’s strongest x-ray sources. The research work is funded by the German Research Foundation (DFG) and the results have just been published in Nature Communications.
Supercooled liquids demonstrate some interesting phenomena when they are irradiated with an extremely bright x-ray source. Shuai Wei, a doctoral student in the Metallic Materials Group headed by Professor Ralf Busch at Saarland University, has been able to observe such phenomena together with research colleagues from DLR are IFW. ‘We have been able to show for the first time that a liquid that is being cooled transforms into a liquid of the same concentration but of greater order, before further cooling initiates crystallisation,’ said Shuai Wei, who graduated with a Bachelor’s degree in physics in Shanghai and has completed his Master’s thesis under the supervision of Professor Busch. Busch and his team are particularly interested in liquid metals that, when cooled, eventually freeze to form bulk metallic glasses. As structural materials, these amorphous metals exhibit some very interesting properties.
Read more at: Phys.org