Two-way tuning of structural order in metallic glasses

Metallic glasses are expected to have quite tunable structures in their configuration space, without the strict constraints of a well-defined crystalline symmetry and large energy barriers separating different states in crystals. However, effectively modulating the structure of metallic glasses is rather difficult. Here, using complementary in situ synchrotron x-ray techniques, we reveal thermal-driven structural ordering in a Ce65Al10Co25 metallic glass, and a reverse disordering process via a pressure-induced rejuvenation between two states with distinct structural order characteristics. Studies on other metallic glass samples with different compositions also show similar phenomena. Our findings demonstrate the feasibility of two-way structural tuning states in terms of their dramatic ordering and disordering far beyond the nearest-neighbor shells with the combination of temperature and pressure, extending accessible states of metallic glasses to unexplored configuration spaces.

Hongbo Lou, Zhidan Zeng, Fei Zhang, Songyi Chen, Peng Luo, Xiehang Chen, Yang Ren, Vitali B. Prakapenka, Clemens Prescher, Xiaobing Zuo, Tao Li, Jianguo Wen, Wei-Hua Wang, Hongwei Sheng, Qiaoshi Zeng, “Two-way tuning of structural order in metallic glasses,” Nat. Commun. 11, 314-1-314-9 (2020). DOI: 10.1038/s41467-019-14129-7 abstract

The relative resistance changes of the Ce₆₅Al₁₀Co₂₅ LOS sample during repeated heating to the different temperatures in the ordering peak of the DSC curve (shown with dash line). It is clear that the resistance decreases obviously once the sample was heated above T₁, and it is irreversible and quenchable to room temperature. b The relative resistance change of the Ce₆₅Al₁₀Co₂₅ HOS sample under compression and decompression. Two different states, HOS and LOS/HP-LOS, are indicated by dashed and dotted lines. The resistance of the sample firstly changes along the dashed line during compression, above ~ 5 GPa it deviates from the initial trend and eventually follows the new trend of the dotted line with a transition zone from ~ 5 GPa to ~18 GPa. The inset displays the image of the HOS sample in the DAC for resistance measurement together with four Pt foil electrodes and a ruby ball for pressure calibration. The scale bar represents 100 μm. The error bars for the resistance and pressure measurements are both smaller than the symbol size.

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