Research institutes from four countries, Hokkaido University, Hong Kong Castle City University (China), Argonne National Research Institute (USA), and Australia Nuclear Science and Technology Organization (Australia), are jointly raising the temperature by making full use of the quantum beam of a large research facility. In-situ observation of nanoscale structural changes in amorphous alloy (metal glass), in the amorphous phase (random region of atomic arrangement inside the material) where the peak of abnormal heat generation in differential scanning calorific value measurement is latent in the supercooled liquid region. For the first time, I clarified something.
Amorphous alloys are non-crystalline alloys in which atoms are randomly arranged.This amorphous alloy has so far many metallic glass with a broad (wide) anomalous exothermic peak between the glass transition temperature (Note) and the crystallization temperature shown by inspection scanning calorific value measurement (thermophysical property measurement method for substances). It has been reported in materials.However, even during the 40-year long study of Pd-Ni-P metallic glass, the best glass-forming alloy, the cause of this abnormal heat generation has been a mystery.
Therefore, the joint research group made full use of quantum beams from different fields in large-scale research facilities (synchrotron radiation, small-angle neutron scattering in nuclear reactors, ultra-high pressure electron microscopes) to generate warm-up amorphous alloys (metal glass). We observed nanoscale structural changes (in-situ observation).As a result, it was clarified that the peak of abnormal heat generation in the differential scanning calorimetry of the amorphous alloy is caused by the amorphous phase latent in the supercooled liquid region.
The results of this research are said to show the way to the development of novel materials by structurally manipulating metallic glass by heat treatment.In addition, it is expected that this will be an opportunity to further promote international joint research and promote the shared use of ultra-high voltage electron microscopes in Japan and overseas.
(Note) Depending on the substance, it remains in a liquid state even below the crystallization temperature (melting point) by quenching (supercooled liquid state), and when the temperature is further lowered, it does not crystallize and becomes an individual (glass state) with a random atomic arrangement. Change.The temperature at this time is called the glass transition temperature.
