On April 13, the research of atomic-resolved in-situ high-temperature mechanics experimental system “Timely and atomic-resolved high-temperature mechanical investigation of ductile fracture and atomistic mechanisms of tungsten” was published on Nature Communications subordinated to Nature, by the research group consisting of Professor Han Xiaodong (co-corresponding author), Researcher Mao Shengcheng (co-corresponding author) of the Institute of Solid Microstructure and Properties, Faculty of Materials and Manufacturing of BJUT, and Academician Zhang Ze of Zhejiang University (co-corresponding author) .

Atom is the basic structural unit that makes up the solid matter. It is the key methodology goal to obtain the atomically resolved material microstructure evolution laws under direct external field action in the fields of microscopy, materials science and physics, chemistry, and even life sciences, and it also lays down an important scientific evidence and foundation for the new material design and process optimization. Atomic-resolved in-situ research method of high-temperature mechanics is an international bottleneck technology, and also a major scientific problem in related fields. In this research, the world’s first and unique (unique technique) “atomic-resolved in-situ high-temperature mechanics research system” was successfully developed based on the service temperature 1,150℃ of nickel-based single crystal superalloy, a typical high-temperature structural material, which filled the relevant gap in the international field; a series of worldwide technical problems were solved, such as the localization of the high temperature field, the sample fracture caused by thermal expansion, and the failure of force driver resulted from the thermal diffusion in the simultaneous application of the high temperature field and the stress field in the millimeter confined space of transmission electron microscope; the smart microchips were designed and prepared, and the ability of atomically resolved in-situ research of the mechanism of material deformation at high temperature above 1,200℃ was obtained for the first time.The system and method are original and hold completely independent and international intellectual property rights, including three US invention patents, one international PCT patent, and 29 Chinese patents. This method was evaluated as “reaching the international leading level” by the acceptance expert group from the National Natural Science Foundation of China.

Based on this system, a systematic study on the basic science problem was carried out to explore the brittle-ductile fracture transition mechanism of BCC structural metals at high temperatures. The ductile fracture mechanism of metal tungsten was found for the first time at the atomic level, revealing the BCC-FCC phase transition and the ductile fracture mode of passivation cracks during the synergy of dislocation movement in the FCC structure. Based on the traditional theory that the high-temperature can enhance the screw dislocation mobility induced ductile fracture, a new high-temperature ductile fracture mechanism in tungsten was discovered.