strength and large elastic limit compared with their crystalline counterparts, [1][2][3] but strain (shear) localization and shear softening associated with the rapid propagation of limited shear bands curtail their ductility and hinder their applications as advanced structural materials. [4][5][6] In principle, strain localization/softening can be mitigated by generating profuse shear bands, obstructing shear band propagation, or inhibiting shear band formation by size reduction. In practice, the plasticity and toughness of MGs can be improved intrinsically by optimizing composition, inhomogeneity, and processing history, extrinsically by introducing soft crystalline phase (such as synthesizing crystalamorphous nanolaminates), or reducing sample dimension to nanoscale. [7][8][9][10][11][12] It is worth mentioning that similar to utilizing the size reduction to suppress instability of deformation of metallic glasses, higher stiffness of testing machine can also alleviate the instability. [13,14] Das et al. attributed the intercepted shear bands in CuZrAl bulk MG to structure inhomogeneity. [15] More than 10% tensile strain was achieved for ZrTi-based bulk metallic glass composites by introducing crystalline dendrites. [12] Also at nanoscale, metallic glasses can deform homogeneously without the formation of shear bands [16] and fracture by necking. [11,17] Studies show that when the sample dimension is ≈10 times of the size of STZs (shear transformation zone) or smaller than ≈100 nm, shear band formation can be inhibited in certain metallic glass systems. [14] Fracture morphology, crack path, and fracture mode, however, were not well understood especially at nanometer length scale. Fracture morphology is directly connected to the mechanism of plastic deformation and fracture toughness. Understanding the patterns of fracture surfaces can be beneficial for the selection and design of MGs with better ductility and toughness, and provides guidelines for modeling and simulations on fracture mechanisms.Thin film metallic glasses (TFMGs) are promising candidates for mirco-electromechanical systems applications, as TFMGs may have high hardness and good fatigue resistance, and can be tailored over a wide range of composition. [4,18] With the addition of crystalline phases, ductility/plasticity of TFMG composites (crystal-amorphous nanolaminates) is improved. [19][20][21][22] For instance, Cu 35 nm/amorphous CuZr 5 nm multilayers can reach ≈14% tensile ductility. [23] Due to their extraordinary mechanical properties, TFMGs can also be potentially utilized in stretchable devices in electronic industry. Therefore, tensileMost metallic glasses are brittle as deformation induces low-density sporadic shear bands and severe shear localization proceeding catastrophic failure. Here, it is demonstrated that the introduction of crystalline nanolayers with appropriate dimension can substantially suppress shear localization in metallic glasses, as manifested by ubiquitous ductile dimples in amorphous phase. Furthermore, dimple sizes c...