Sample size effects on strength and deformation mechanism of Sc75Fe25 nanoglass and metallic glass

Abstract

The mechanical properties and deformation mechanism of Sc 75 Fe 25 nanoglass and Sc 75 Fe 25 metallic glass pillars with diameter from 2 micrometers to 95 nanometers were investigated by means of ex-situ and in-situ compression tests. The results showed that the yield strength and deformation mechanism in the metallic glass were size-dependent while these in the nanoglass were not. It is suggested that the reduced shear band nucleation sites in metallic glass with decreasing sample size results in the increased yield strength and transition of deformation mode. In contrast, the glass/glass interfaces in nanoglass which have reduced density could serve as shear band nucleation sites and therefore promote multiple shear banding.

Interfacial plasticity governs strain delocalization in metallic nanoglasses

“…These length scales have important implications for size effects in plasticity. Extrinsic size effects common in monolithic metallic glasses [23,24,25] have been shown to be absent in nanoglasses albeit only over a narrow size range [26] and attributed to distributed plasticity promoted by the heterogeneities in the underlying amorphous structure. However, these heterogeneities are simultaneously responsible for an intrinsic size effect akin to the scaling behavior that derives from the role of microstructural length scales on plasticity in crystalline solids.…”

Ni-P nanoglass prepared by multi-phase pulsed electrodeposition

“…As an example, it has been found that a Fe 90 Sc 10 nanoglass is ferromagnetic at 300 K, whereas the corresponding melt-quenched glass is paramagnetic, and only exhibits ferromagnetic order at a temperature below 200 K [5]. Moreover, nanoglasses have been reported to be more ductile, more biocompatible, and catalytically more active compared to the corresponding melt-quenched glasses [6][7][8][9][10][11][12][13][14]. Hence, by modifying the microstructure of nanoglasses using controlling the size of the amorphous grains (i.e.…”

Mechanical Properties of Glassy Nanopillars: A Comparative, Computational Study of Size Effects in Nanoglasses and Homogeneous Bulk Glasses

“…Moreover, a systematic study of nanosized and microsized Sc 75 Fe 25 HG and NG pillars by means of compression tests showed that both, yield strength and deformation mode, are size-dependent in HG pillars. These properties, however, are size-independent in the NG pillars (Wang et al, 2016b), which was attributed to the microstructural features present in the NG. Indeed, molecular dynamic (MD) simulations revealed that glass-glass interfaces in NGs act as nucleation sites for shear transformation zones (STZs) and prevent strain localization, which leads to the more homogeneous deformation of NGs as compared with HGs (Şopu et al, 2011;Adibi et al, 2013;Albe et al, 2013;Adibi et al, 2014;Şopu and Albe, 2015;Adjaoud and Albe, 2019;Cheng and Trelewicz, 2019b).…”