The 8th International Conference on Matter and Radiation at Extremes (ICMRE2025)

190 / 2025-03-20 16:18:23

Homogeneous Plastic deformation of metallic glass under high pressure

High pressure,glass,deformation,synchrotron x-ray

The unique disordered dense packing atomic structure of metallic glass endows it with many exceptional properties, such as high strength and hardness, wear resistance, etc. However, the plastic deformation of metallic glass at room temperature often localizes within narrow shear bands, leading to a typical absence of macroscopic plasticity. Overcoming this issue requires an in-depth understanding of the structural mechanisms governing the deformation of metallic glass. In contrast to crystalline materials, where the structural carriers of plastic deformation, such as dislocations and grain boundaries, are well-defined, the disordered structure of metallic glass poses significant challenges in precisely describing the structural carriers of plastic deformation. Currently, the most fundamental understanding is that the plastic deformation of metallic glass is always accompanied by shear dilatation, which naturally implies that pressure has a significant impact on the deformation of metallic glass and can be an important regulatory parameter. Here, using a simple binary metallic glass, Zr65Ni35, as a model system, we conducted in-situ investigation of its deformation under pressure using high-pressure in-situ synchrotron X-ray nanotomography (TXM). According to synchrotron X-ray diffraction data, we confirmed that the sample maintained a purely amorphous structure without any phase transformation involving volume discontinuity. Interestingly, we confirmed that its plastic deformation became “homogeneous” under high pressure without any offsets on the sample surface. A few microns thick low-density regions were revealed after the plastic deformation. Furthermore, in-situ high pressure indentation experiments using ruby balls further confirmed the shear dilatation behavior at the micron scale under high pressure. These findings provide new approaches for studying the mechanisms of plastic deformation in metallic glass and for understanding and controlling shear bands in metallic glasses.