Figure. Schematic diagram of the liquid metal-assisted synthesis process

Under the support of the National Natural Science Foundation of China (Grant Nos. 22025303、21905210、11974156), Professor Lei Fu’s research group from Wuhan University, in collaboration with Professor Yuzheng Guo’s research group from Wuhan University and Assistant Professor Junhao Lin’s research group from Southern University of Science and Technology, have realized the atomically-precise synthesis (i.e. atomic manufacturing) of diverse high-entropy alloys through using liquid metals as reaction medium. The research results were published in Nature on June 14, 2023, titled “Liquid metal for high-entropy alloy nanoparticles synthesis”. (Full article link at https://www.nature.com/articles/s41586-023-06082-9).

High-entropy alloys (HEA) are usually consisted of more than five metal elements, whose precise synthesis is of great significance. As a new type of alloy that breaks through the traditional alloy design concept, HEAs exhibit unique and exceptional properties, promising for various applications, such as catalysis, mechanical and biomedical fields. However, the vast difference in physical and chemical properties among various elements hinders the realization of high entropy mixing. The current approaches mainly utilize high-temperature and ultra-fast cooling processes to alloy multiple elements and maintain the high-entropy mixing state, which is not conducive to the further fine regulation of HEAs.

To solve this problem, the research group put forward a strategy of liquid metal for the atomic manufacturing of HEAs. Liquid metal endowed negative mixing enthalpy with other metal elements, reflecting the interaction force between elements with affinity. Meanwhile, the unique low-temperature fluidity of liquid metal could facilitate the dynamic mixing of various elements. This provided the feasibility of liquid metal-assisted atomic manufacturing toward HEAs. The strategy exhibited good applicability to multiple HEA systems, where different elements with distinct preferred crystal structures, melting points, and atomic radii could be precisely manufactured. The transmission electron microscopy (TEM) characterization indicated homogenous elemental mixing and high-quality crystallinity of HEAs. During the process of liquid metal-assisted synthesis of HEAs, the dynamic fission-fusion behavior and crystallization phenomenon have been observed via in situ environmental TEM and in situ synchrotron radiation X-ray diffraction experiments. The dynamic simulation based on the machine learning potential also verified this mechanism. The research expands the atomic manufacturing methodology based on liquid metals and provides a new idea for the atomically-precise synthesis of advanced materials.