Impact resistance of single-layer metallic glass nanofilms to high-velocity micro-particle penetration

Macro- and microscale metallic glasses exhibit excellent protective capability under hypervelocity projectile impact conditions. However, it is formidably challenging to evaluate the ballistic performance of metallic glasses with characteristic sizes down to the nanoscale. Here, we adopt the laser-induced micro-particle impact technique to penetrate 60-nm-thick Ni60Ta40 metallic glass nanofilms with projectile velocities in the range of 186–540 m/s. Based on the ballistic analysis, the superior impact resistance of the metallic glass nanofilms is quantitatively characterized in terms of the specific penetration energy. The post-mortem observations of the penetration features reveal that shear-banding, cracking, and bending of cracking-induced petals are the main energy dissipation modes beyond the localized perforated hole, which is strongly dependent on impact velocities. This work for the first time achieves high-strain-rate loading on nanoscale metallic glasses, and extends their engineering applications as promising armor materials for high-velocity impact protection.