Effect of Surface Mechanical Attrition Treatment on Micro-mechanical Properties of ZrCuAlNi Bulk Metallic Glass

Abstract

In this work, surface mechanical attrition treatment (SMAT) was employed to rejuvenate ZrCuAlNi bulk metallic glass (BMG) plate. Differential scanning calorimetry (DSC), atomic force microscopy (AFM) and nanoindentation analyses were carried out to evaluate stored energy and micro-mechanical properties of treated BMGs. According to DSC results, 10 min SMAT process increased the stored energy of BMG plates up to 50%. AFM analysis showed that the structural rejuvenation occurred in the bulk of samples and just a slight rejuvenation gradient was detected from the front to the back side of BMG plates. Nanoindentation analysis indicated that the structural rejuvenation is consistent with anelastic strain induced under the SMAT process. It was also found that an optimum treatment time is needed for maximum rejuvenation in the BMGs. This event is due to the fact that the glassy structure is able to store a critical anelastic strain, which leads to a saturated condition in rejuvenation.