Quantitative analysis of the mechanism and influencing factors of mechanical fracture-induced light emission of Zr-based bulk metallic glasses

Abstract

The catastrophic fracture of bulk metallic glasses (BMGs) during mechanical deformation is generally accompanied by the unique light emission with extremely high flash temperature. This seriously endangers the application of BMGs in engineering. Without suitable quantitative characterization methods, the underlying mechanism and influencing factors of light emission remain unclear. Herein, from the perspective of photometry, a spectroradiometer is used to characterize the brightness, spectrum, and color temperature of light emission from compressive fracture of Zr-based BMGs. Specifically, the brightness physical target serves as the intensity index to quantify the variation of light emission with external conditions. The atmospheric environment compression tests are conduct to reveal the underlying mechanism of light emission generation. Moreover, the influence of sample size, strain rate and material composition on light emission is quantified by the brightness. The results reveal that the light emission from the mechanical fracture of Zr-based BMGs is due to the spontaneous combustion of sample particles with a large specific surface area and a high energy density. The energy density of fractured surfaces and elemental composition of Zr-based BMGs are intenral factors that influence light emission. Increasing the sample size or reducing the strain rate can lead to an increase in energy density, resulting in enhanced light emission. The alloy elements with high oxidation exothermic enthalpy inside the material participate in the combustion reaction of particles, which also significantly increases the intensity of light emission. These findings provide useful insights into the avoidance of mechanical fracture-induced light emission in BMG engineering applications.