Correlation between mechanical and thermodynamic properties for La–Ce–Ni–Cu–Al high-entropy metallic glasses
The mechanical properties, thermodynamic features and their correlation were studied for La–Ce–Ni–Cu–Al high-entropy bulk metallic glasses (HE-BMGs). Compressive testing indicated that the HE-BMGs are ductile on a microscopic scale but brittle on a macroscopic scale, because of the low fragility index m of the HE-BMGs. In the non-isothermal process, the activation energies for glass transition for these HE-BMGs are the lowest of the known HE-BMGs. Large values of the Avrami exponent n imply that the crystallization process proceeded through three-dimensional growth and with an increasing nucleation rate. The activation energy for glass transition (Eg) is almost proportional to the HE-BMG fracture strength, because a higher Eg is required to dislodge the molecules from the glassy configuration for the HE-BMGs with a high strength. The findings provide unambiguous evidence for the correlation between the mechanical and thermodynamic properties.
KeywordsHigh-entropy bulk metallic glass Fracture mechanism Crystallization Avrami exponent Glass-transition activation energy
This work was supported by the National Key Research and Development Project of China (2016YFB0300500), MOST 973 Program (No. 2015CB856800), NSF of China (Grant No. 51571079) and the Fundamental Research Funds for the Central Universities in China (No. JZ2016HGPB0671).
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