Fig. 1 Schematic illustration of the preparation process for 2024 Al/TC4 laminated composites

Fig. 2 a SEM micrographs of the interface, b EDS mapping of Al in a, c EDS mapping of Cu in a, d EDS mapping of Ti in a, e EDS mapping of Mg in a

Fig. 3 a SEM micrographs of the interface, b EDS point scans of point A, c EDS point scans of point B, d EDS point scans of point C, e EDS point scans of point D, f XRD pattern of the growth layer annealed for 2 h and 32 h

Fig. 4 Ti-Al binary phase diagram by Pandat software

Fig. 5 SEM micrographs of the 2024 Al/TC4 laminated composites: a annealing 0 h, b annealing 2 h, c annealing 8 h, d annealing 16 h, e annealing 24 h, f annealing 32 h

Fig. 6 EDS line scans of the growth layers of 2024 Al/TC4 laminated composites: a annealed 0 h, b annealed 2 h, c annealed 8 h, d annealed 16 h, e annealed 24 h, f annealed 32 h

Fig. 7 a Relationship between Al3Ti layer thickness and annealing time, b SEM image of the interface of annealed 8 h, c SEM image of the interface of annealed 16 h

Fig. 8 Phase distribution diagram: a annealed 2 h, b Al side at annealed 32 h, c Ti side at annealed 32 h; Grain boundary distribution diagram d Annealed 2 h, e Al side at annealed 32 h, f Ti side at annealed 32 h; Histograms of the grain size distribution and cumulative frequency curves of Al3Ti grains: g annealed 2 h, h Al side at annealed 32 h, i Ti side at annealed 32 h

Fig. 9 Stress-strain curves of 2024 Al/TC4 laminated composites with different annealing time

Fig. 10 Crack morphology of 2024 Al/TC4 laminated composites after three-point bending test: a annealed 0 h, b annealed 2 h, c annealed 8 h, d annealed 16 h, e annealed 24 h, f annealed 32 h

Fig. 11 Growth law of the Al3Ti: a initial conditions at the interface, b nucleation of Al3Ti, c formation of the diffusion layer, d growth stage

Fig. 12 Formation of the diffusion layer: a initial conditions, b Ti atom cluster

Fig. 13 a KAM maps of 2024 Al/TC4 laminated composites after annealing for 2 h, b KAM statistics of 2024 Al layer, c KAM statistics of Al3Ti layer, d KAM statistics of TC4 layer

Fig. 14 a IPF maps of 2024 Al/TC4 laminated composites along the bending direction, b pole figure of the 2024 Al layer after bending, c pole figure of the TC4 layer after bending, d IPF magnified image of the 2024 Al layer after bending in a, e IPF magnified image of the TC4 layer after bending in a

Fig. 15 Schematic diagram of crack extension in 2024 Al/TC4 laminated composites: a-c the early stage of loading, d-f the middle stage of loading, g-i the end stage of loading

Fig. 16 a Morphology at the interface after annealing for 8 h, b local magnification of the diffusion layer in a, c local magnification of the diffusion layer in a, d mopography at the interface after annealing for 16 h

Fig. 17 Crack evolution under different dislocation conditions: a1-c1 an interface without dislocations; a2-c2 an interface with dislocations. (Note: The white dotted line represents the interface between the growth and diffusion layers, the red rhombic structure indicates dislocations on large-angle grain boundaries, the green atomic region is the initial crack, the red atomic position is the dislocation, the red acute-angle structure indicates that the crack extension tip is acute, the yellow arc structure indicates crack passivation, and the yellow arrow indicates the direction of crack extension.)

Fig. 18 Free energy curves for crack extension in dislocation-free zone and high-density dislocation zone: a T* = 2000, b T* = 7000, c T* = 11,000