The synthesis of advanced thin film metallic glasses (TFMGs) with engineered microstructures capable to provide a large combination of mutually exclusive mechanical properties (i.e. high strength and ductility) mitigating the shear band (SB) instability, is an open research topic. Here, I will present recent results involving two (2) strategies to finely tune the microstructure of TFMGs by introducing controlled local heterogeneities (nanointerfaces, crystalline nanolayers, nanoclustering), resulting in large and tunable mechanical behavior. Firstly, I will show the fabrication of fully amorphous Zr24Cu76/Zr61Cu39 nanolaminates by magnetron sputtering with controlled nanoscale periodicity (Λ, from 400 down to 5 nm), local chemistry and glass-glass interfaces (Fig. 1a) [1]. I will show how the SB instability can be mitigated when Λ≤50 nm, reaching remarkably large elastic/plastic deformation (16%) and yield strength (~2GPa) by micro-pillar compression, while highlighting significant chemical intermixing by HRTEM and APT during SB process (Fig. 1a) [1]. Then, I will show the potential of Pulsed Laser Deposition (PLD) as a novel technique to synthetize nanostructured Zr50Cu50 (%at.) TFMGs. I will show how the control of PLD process parameters enables to synthetize a variety of film microstructures among which fully amorphous compact and nanogranular reporting a large free volume content [2]. This results in an unique and tunable mechanical behavior as shown by in situ TEM/SEM tensile & compression tests, reporting homogeneous deformation combined with a large yield strength (>3 GPa) and ductility (>9 %) product [2]. Finally, I will focus on the synthesis of compact and nanogranular crystal/glass ultrafine nanolaminates (U-NLs) by PLD in which ∼4 nm Al (crystalline) separate 6 and 9 nm-thick Zr50Cu50 (MG) nanolayers, reporting a high density of sharp interfaces large chemical intermixing (Fig. 1b). Among the main results, nanogranular U-NLs report high yield strength (3.4 GPa) in combination with enhanced elastoplastic deformation (>6%, in compression). Moreover, this structure effectively block the percolation of SBs even reaching >15% deformation as a result of the larger free volume content and the presence of ultrafine crystal-glass nanointerfaces (Fig. 1b). Overall, I will show how managing microstructural heterogeneities in TFMGs is an effective strategy to control their deformation behavior, boosting their mechanical properties with potential for industrial applications. REFERENCES: [1] A. Brognara et al., Tailoring mechanical properties and shear band propagation in ZrCu metallic glass nanolaminates through chemical heterogeneities and interface density, submitted to Small Structures (2024). [2] M. Ghidelli et al., Novel class of nanostructured metallic glass films with superior and tunable mechanical properties, Acta Mater., 213, 116955, 2021. [3] F. Bignoli et al., Novel class of crystal/glass ultrafine nanolaminates with large and tunable mechanical properties, submitted to ACS Materials and Interfaces (2024).