Metal-hydrogen systems have attracted intense interest for diverse energy-related applications. However, metals usually reduce their ductility after hydrogenation. Here, we show that hydrogen can take the form of nano-sized ordered hydrides (NOH) homogeneously dispersed in a stable glassy shell, leading to remarkable enhancement in both strength and ductility. The yield strength is enhanced by 44% and the plastic strain is substantially improved from almost zero to over 70%, which is attributed to the created NOH and their interplay with the glassy shell. Moreover, the hydride-glass composite GdCoAlH possesses a giant magnetic entropy change (−ΔS_M) of 18.7 J kg⁻¹K⁻¹ under a field change of 5 T, which is 105.5% larger than the hydrogen-free sample and is the largest value among amorphous alloys and related composites. The prominent ΔS_M-ductility combination overcomes the bottlenecks of amorphous alloys as magnetic refrigerants. These results provide a promising strategy for property breakthrough of structural-functional alloys.

The effect of uniaxial elastostatic compression on the deformation behavior of the Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 (Vit1) bulk metallic glass (BMG) was reported. The as-cast alloy was pre-compressed under various time (20, 40 and 60 h) at a preloading level of 87% of its yield strength. It was found that elastostatic compression can lead to structural rejuvenation or relaxation depending on the pre-compression time. Elastostatic compression, for 40 h, increased the free volume and improved the plasticity of the BMGs from 1.4% to 3.4%, but preloading for 60 h decreased the free volume and worsened the plasticity. In addition, the heterogeneous structure evolution during creep deformation has been analyzed by the Maxwell-Voigt model with two Kelvin units, revealing that more (less) defects with larger size are activated after elastostatic compression treatment for 40 h (60 h). This work sheds new light on the correlation between heterogeneous structure and plasticity/creep behaviors of Zr-based BMGs.

Metallic glasses (MGs) possess the merits of high strength and a large elastic limit. However, they suffer from little tensile ductility in the inhomogeneous deformation regime due to strain softening and shear localization. In this work, we report a substantial increase in tensile plastic strain (ε_p) from 2.8% to 10% in a Fe-based metallic glass (MG) via non-affine thermal strain (NTS), accompanied by a significant intensity enhancement and a considerable decrease in activation energy (32%) of the β-relaxation. Notably, pronounced strain hardening is observed during tension. These extraordinary tensile properties are structurally attributed to the NTS-promoted formation of a chemical-fluctuation-mediated network structure consisting of interconnected Fe-rich medium-range orders (MROs) and surrounding metalloid-rich clusters, as well as the subsequent temperature and stress-induced unique evolution of the multiscale structural heterogeneities. Specifically, the stress-induced unique MRO formation, α-Fe nanocrystallization, and the irreversible relaxation-induced structural ordering jointly interact with shear banding to transform strain softening into hardening, leading to excellent ductility. These findings demonstrate that simultaneous relaxation-assisted and transformation-mediated deformation stabilizes the inhomogeneous plastic flow under tension, overcoming the ductility bottleneck of MGs.

Comprehending the pressure-/temperature-induced structural transition in glasses, as one of the most fascinating issues in material science, is far from being well understood. Here, we report novel polyamorphic transitions in a Cu-based metallic glass (MG) with apparent nanoscale structural heterogeneity relating to proper Y addition. The low-density MG compresses continuously with increasing pressure, and then a compression plateau appears after ∼8.1 GPa, evolving into an intermediate state with an ultrahigh bulk modulus of ∼467 GPa. It then transforms to a high-density MG with significantly decreased structural heterogeneity above ∼14.1 GPa. Three-dimensional atom probe tomography reveals concentration waves of Cu/Zr elements with an average wavelength of ∼5–6 nm, which promote the formation of interconnected ringlike networks composed of Cu-rich and Zr-rich dual-glass domains at nanometer scale. Our experimental and simulation results indicate that steplike polyamorphism may stem from synergic effects of the abnormal compression of the Zr–Zr bond length at the atomic scale and the interplay between the applied pressure and incipient concentration waves (Cu and Zr) at several nanometer scales. The present work provides new insights into polyamorphism in glasses and contributes to the development of high-performance amorphous materials by high-pressure nanostructure engineering.