Relationship between structural heterogeneity and serrated flow in nanoscale phase separated Zr-Cu-Fe-Al bulk metallic glasses

In this work, the relationship between structural heterogeneity and serrated flow in nanoscale phase separated Zr-Cu-Fe-Al bulk metallic glasses with different plasticity was investigated. The results showed that liquid-liquid phase separation would occur during rapid cooling of Zr59(Cu1-xFex)33Al8 (x = 0.4 and 0.5) alloys, resulting in the microstructure formation of amorphous FeZr-rich nanoparticles embedded in the amorphous CuZr-rich matrix. The compression test and statistical analysis indicated that serration dynamics transforms from a chaotic state with a characteristic length scale of stress drop to a self-organized critical (SOC) state with the increase of the atomic ratio of Cu to Fe. This transformation is ascribed to the increase of the number of nucleation sites for shear transformation zones with the increase of structural heterogeneity, which is conducive to the formation of multiple shear bands. This work will be helpful to understand the relationship between the microstructure and deformation behavior.

Automated summary

This work investigates the relationship between structural heterogeneity and serrated flow in nanoscale phase separated Zr-Cu-Fe-Al bulk metallic glasses with different plasticity. The results show that as the atomic ratio of Cu to Fe increases, serration dynamics transform from a chaotic state to a self-organized critical state. This transformation is attributed to the increase in structural heterogeneity, which promotes the formation of multiple shear bands.