Extending mechanical size effect range of thin film metallic glasses by nanoengineering their atomic and nanostructure

Nanoscale metallic glasses (MGs) have demonstrated unique strength – ductility balance with a yield strength close to the theoretical limit and large homogeneous plastic deformation, mitigating the shear band (SB) instability. However, such mechanical size effects are triggered only for intrinsic sample dimensions below few hundreds of nm, reducing their application range. In this work, we present a novel synthesis strategy to fabricate nanostructured thin film metallic glasses (TFMGs) with tailored local heterogeneities by exploiting the potential of Pulsed Laser Deposition (PLD), managing to extend MG’s mechanical size effect range up to the micrometer scale. We realize this by synthetizing model Zr 50 Cu 50 and Zr 46 Cu 46 Al 8 TFMGs with controlled nanostructure compact and nanogranular, exploiting atom-by-atom and cluster-assembled growth regimes. PLD-deposited TFMGs have unique atomic structures as observed by synchrotron X-ray scattering, with high mass density, resulting in enhanced elastic modulus (up to 120 GPa) and hardness (up to 8.6 GPa), significantly above sputter-deposited counterparts. Moreover, PLD-deposited TFMGs exhibit high yield strength ( σ y >2.8 GPa) and up to 6.7 % elastoplastic deformation which are maintained even at high strain rates up to 10 s -1 for large micropillar dimension of 1.3 × 3 µm (diameter x height). Such values significantly surpass those of traditional families of bulk and TFMGs, where size effects on σ y and plasticity are activated for intrinsic dimensions < 0.5 µm. Overall, we show that PLD can produce nanostructured TFMGs with high strength and plasticity balance kept for large intrinsic dimensions, opening a new synthesis approach for strong and ductile materials.