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The serrated plastic flow,microstructure and residual stress of a Zr_(55)Cu_(30)Ni_5Al_(10) bulk metallic glass(BMG)undergone surface mechanical attrition treatment(SMAT)have been investigated by a combination of compression tests with scanning electron microscopy(SEM),high resolution transmission electron microscopy(HRTEM)and the incremental hole-drilling strain-gage method.It is found that SMAT leads to various microstructural modifications and residual stress distribution in the surface layers of the Zrbased BMG due to the mechanically-induced nanocrystallization and generation of shear bands.As a result,the BMG alloy exhibits a remarkable work-hardening like behavior and significant increase of plastic strain from less than 1%to 15%,and its plastic deformation dynamics yields a power-law distribution of shear avalanches.Based upon the analysis of the experimental results,it is indicated that this can be connected to the SMAT-induced microstructural modifications and the resulting residual compressive stress in the Zr-based BMG.
The serrated plastic flow, microstructure and residual stress of a Zr 55 Cu_ (30) Ni_5Al 10 bulk metallic glass (BMG) undergone surface mechanical attrition treatment (SMAT) have been investigated by a combination of compression tests with scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and the incremental hole-drilling strain-gage method. It is found that SMAT leads to various microstructural modifications and residual stress distribution in the surface layers of the Zrbased BMG due to the mechanically- induced nanocrystallization and generation of shear bands.As a result, the BMG alloy exhibits a remarkable work-hardening like behavior and significant increase of plastic strain from less than 1% to 15%, and its plastic deformation dynamics yield a power-law distribution of shear avalanches.Based upon the analysis of the experimental results, it is indicated that this can be connected to the SMAT-induced microstructural modifications and the resulting r esidual compressive stress in the Zr-based BMG.