Slip Statistics for a Bulk Metallic Glass Treated by Cryogenic Thermal Cycling Reflect Its Optimized Plasticity

Abstract

Enhanced plasticity is obtained in a structurally rejuvenated Zr-based bulk metallic glass (BMG) that has been treated via cryogenic thermal cycling (CTC) for one hundred cycles. More than one primary shear band is activated due to the structural rejuvenation, which can inhibit the jerky and system-spanning propagation of shear bands to generate sluggish shear-dynamics. These are mapped to the slip statistics, including the decreased critical avalanche size, the much longer avalanche duration of large (system-spanning) slips, and a great number of small avalanches. Moreover, the universal scaling of slip avalanches for three applied stress ranges is addressed to predict the applied stress at which the failure avalanche appears most. These results indicate that slip statistics can be the fingerprints to show how much the BMG is rejuvenated, and the failure avalanche provides a good opportunity to intervene in the failure of BMGs in advance.

Keywords

• bulk metallic glasses
• plasticity
• shear bands
• slip avalanches
• cryogenic thermal cycling