Wavelike fracture pattern in a metallic glass: a Kelvin–Helmholtz flow instability

Abstract

We report a wavelike fracture pattern in a Zr-based bulk metallic glass that has been deformed under quasi-static uniaxial tensions between room temperature (300 K) and liquid nitrogen temperature (77 K). We attribute this wavelike pattern to a Kelvin-Helmholtz flow instability that occurs at certain interfaces between local cracking/softening regions. The instability criterion for the pattern formation is achieved via a hydrodynamic perturbation analysis, and furthermore, an instability map is built which demonstrates that the shear velocity difference on both sides of the interface is the main destabilizing factor. Finally, the characteristic instability time (the inverse of the instability growth rate) is explored by seeking the dispersion relation in the dominant (fastest) instability mode. The results increase the understanding of the flow and fracture of metallic glasses as well as the nature of their liquid structures.

Simulation of Nanoparticles Formation by Mechanism of Kelvin-Helmholtz Instability

“…The linear analysis of the Kelvin-Helmholtz instability developed in our works [1][2][3] to various technological problems is presented in [19]. A mechanism and a mathematical model for the formation of shear bands from the position of the Kelvin-Helmholtz instability are proposed in [20]. Within the framework of this model, a neutral curve is obtained, which allows us to determine only the conditions for the onset of instability.…”

Mechanical response of Ti-based bulk metallic glass under plate-impact compression

“…4e), substantial vein-like patterns formed, meanwhile, wavelike patterns formed at the boundary of vein-like patterns (marked by wave lines). These wave-like patterns were also found in Zr-based BMG under quasi-static uniaxial tension, which were attributed to the KelvineHelmholtz flow instability of fluids in the interfaces between the local cracking or/and softening regions [26]. Further examination of zone Ⅲ (marked by rectangle in Fig.…”