Fig. 1 a DSC profiles for Z0 and Z2. The heating rate is 10 K/min. The inset figure is an enlarged view near the melting point. The glass transition temperature Tg, crystallization temperature Tx, and the liquidus temperature Tl are marked by arrows. b Two-dimensional contour plots of in situ SAXS profiles for Z2 during heating. The inset figure is the pair distance distribution function of the different states for Z2. c In situ evolution of radius of gyration Rg, exponent n, and surface fractal dimension Ds changes as functions of the temperature. d Porod’s analysis results for Z2 upon heating

Fig. 2 In situ high-energy synchrotron X-ray results of Z0 and Z2 BMGs upon heating. a, b Two-dimensional contour plots of S(Q) of Z0 and Z2 as a function of Q and scanning temperature; c, d structure factor S(Q) at different temperatures of Z0 and Z2 BMGs, respectively

Fig. 3 Rietveld refinement results for a Z0, b, c Z2 in different crystallization stages. The position of characteristic peaks of crystallization products is indicated by arrows. The right side is ball-stick models of crystalline products for each alloy

Fig. 4 Temperature dependence of characteristic peaks’ intensity for crystalline products versus DSC for a Z0 and b Z2. The black dotted line marks the crystallization temperature. The integration ranges for Z0 are 2.589-2.599 Å-1. The integration ranges of the first crystalline diffraction pattern for Z2 are 2.664-2.674 Å-1 (red dots), and the integration ranges for the second crystalline stage are 2.439-2.449 Å-1 (yellow dots, the characteristic peak position of the Cmcm Zr3Fe) and 2.549-2.559 Å-1 (blue dots, the characteristic peak position of the I4/mmm Zr2Cu). Arrows of the same color mark the integrated positions in Fig. 3

Fig. 5 HRTEM images of Z2 annealed at Tx1 a. The inset of each image is its corresponding electron diffraction patterns. The HAADF b EDS element mapping c for the first-stage crystallization product of Z2. The green, yellow, red, and purple mapping represents Zr, Cu, Fe, and Al, respectively

Fig. 6 Two-dimensional contour plots of neutron a synchrotron b G(r) profiles of Z2 as a function of temperature. The differential neutron c synchrotron d G(r) profiles of Z2 were obtained by subtracting the as-cast data by neutron and synchrotron diffraction

Fig. 7 a Differential G(r) of as-cast Z2, the first crystallization stage (755 K), and the second crystallization stage (846 K) obtained by neutron and synchrotron diffraction. b Calculated G(r) patterns based on standard CIF files obtained using PDFgui software and the experimental G(r) patterns (black lines) at the first crystallization stage obtained by neutron (dotted lines) and synchrotron (solid lines) diffraction. The calculated PDF pattern Fd-3 m Zr2Cu is the red line (inset: the enlarged region). c Experimental G(r) of Z2 upon in situ annealing up to 500 s by synchrotron high-energy X-ray diffraction. d Integrated intensities of G(r) profiles. The position with more Cu-related bonds corresponds to the integrated r range of 10.14-10.15 Å (red dotted line). The position with more Fe-related bonds corresponds to the integrated r range of 11.42-11.43 Å (blue dotted line)

Fig. 8 Engineering stress-strain curves of as-cast, initial crystalline state, and final crystalline state Z2 rods