Fig. 1. Thermal behavior and atomic structural variations among different glass states. (a) Heat capacity curves for Pd40Ni40P20 BNG and BMG samples scanned at a rate of 10 K min-1. A total enthalpy release of 2021 J mol-1 can be calculated based on the shadowed region below the Tg. For ease of differentiation, the BMG curve is shifted down by 40 J mol-1. (b) Composition mapping by 3D atomic probe tomography, showing homogeneous Pd, Ni, and P element distribution at the nanoscale in Pd40Ni40P20 BNG alloy. (c) Structure factor S(Q) patterns for BNG, NPs, and BMG samples. The inset shows the magnification of the first sharp diffraction peaks of S(Q) patterns. The dash lines indicate peak positions. (d) Reduced pair distribution function, G(r), for Pd40Ni40P20 BNG, NPs, and BMG sample. The inset shows the proportion of four kinds of connection mode among three samples.

Fig. 2. Revealing nanoscale heterogeneity by small-angle scattering. (a) Synchrotron small-angle X-ray scattering (SAXS) log-log plots for the Pd40Ni40P20 BNG and BMG samples. (b) Small-angle neutron scattering (SANS) log-log plot for the Pd40Ni40P20 BNG. The red line is the model fitting based on the spheroid model with polydispersity. The inset shows the pair distance distribution function based on the SANS profile. (c) The integrated intensity (over the range of 0.02-0.3 Å-1) of in-situ SAXS vs. temperature for the Pd40Ni40P20 BNG sample. The red circle line represents the 1st heating run from RT to 500 K, and the blue circle line represents the 2nd heating run from RT to 700 K, both at a rate of 10 K min-1. A canary square marks TS region at ～ 400 K, and a vertical dotted line marks Tg at 558 K. Black dotted lines are linear fitting results to show the slope changes. (d) The integrated intensity (over the range of 0.02-0.3 Å-1) of in-situ SAXS vs. temperature for the Pd40Ni40P20 BMG sample. The arrow indicates the slope change at TX.

Fig. 3. Nanoscale structure characterization during the synthesis process of Pd40Ni40P20 BNG. High-resolution TEM images for (a) Pd40Ni40P20 BMG, (b) NPs, (c) Pd40Ni40P20 BNG at RT, and (d) Pd40Ni40P20 BNG annealed at 500 K are exhibited. No noticeable contrast could be observed to distinguish the interfacial regions from the matrix in BNG samples. Insets are selected area diffraction patterns for each sample, confirming their amorphous nature.

Fig. 4. In situ X-ray diffraction data. (a) Evolution of structure factor S(Q) for Pd40Ni40P20 BNG sample during heating at a rate of 20 K min-1. (b) Difference ΔS(Q) plots obtained by subtracting the diffraction pattern at 303 K. (c) Temperature dependence of the first moment Q1 and specific heat CP for Pd40Ni40P20 BNG. Yellow dotted lines are linear fitting of the data at different temperature ranges to show the slope changes at TS and Tg. (d) The peak heights of Q1 and Q2 as a function of temperature. The solid lines are the eyes' guide.

Fig. 5. Structure analysis in real space upon heating. (a) Reduced pair-distribution function G(r) at different temperatures. The arrows indicate the first coordination shell (R1), second coordination shell (R2), and fifth coordination shell (R5). The baseline G(r)=0 is superimposed for reference. (b) Difference G(r) plots obtained by subtracting the pattern at 303 K. (c) Integrated intensity of R1, R2, and R5 (for regions where G(r)>0). (d) Integrated g(r) intensities in the vicinity of four positions representing the four SRO clusters connection modes, respectively. Integration r ranges for 1-atom, 2-atom, 3-atom, and 4-atom modes are 5.30-5.32 Å, 4.59-4.61 Å, 4.33-4.35 Å, and 3.75-3.77 Å, respectively.

Fig. 6. Negative thermal expansion of MRO between TS and Tg for the Pd40Ni40P20 BNG. (a) 2D contour plot for differential G(r) profile of Pd40Ni40P20 BNG. Higher coordination shells shift left with the temperature increasing above TS, indicating the structure change at MRO. (b) Peak positions evolution for R1 and R5 of G(r) during heating, which corresponds to the 2D contour plot and implies a negative expansion phenomenon between TS and Tg.

Fig. 7. Nanoindentation results. (a) Evolution of modulus and hardness of Pd40Ni40P20 BNGs annealed at selected temperatures. (b) Load-displacement plot for Pd40Ni40P20 BNG during nanoindentation measurements. The curve at RT is smooth while serrations (pop-in events as marked by blue arrows) appear with the increase in temperature.

Fig. 8. Ab initio molecular dynamics simulations. A nine-coordinated P-centered cluster of TTP was utilized to represent the short-range order in the Pd-Ni-P BNG. The cluster recovers to TTP after undergoing a heating/cooling process.