Temperature-Induced Structural Changes in the Liquid GaInSn Eutectic Alloy

The temperature-dependent structure and properties of a liquid GaInSn eutectic alloy have been investigated by using in situ high-energy X-ray diffraction, thermal expansion, and heat capacity measurements together with ab initio molecular dynamics simulations. It is found that below and above 550 K, the liquid exhibits differences in heat capacity, density, the first two peak positions of the structure factor and pair distribution function, partial coordination numbers, polyhedron connection, as well as Bader charge and Bader volume of In atoms. Both experimental and theoretical results obtained here clearly reveal a liquid-to-liquid crossover in the liquid GaInSn eutectic alloy at around 550 K, which mainly originates from the aggregation of In atoms upon cooling together with Sn atoms tending closer to In. The finding here deepens the understanding of the disorder-to-disorder transition in disordered materials.