Fig. 1 Schematic diagrams of the flake PM producing route of CNTs/Al composites [4]

Fig. 2 SEM images showing the distributions of absorbed CNTs a, GO b, native Al2O3 flakes c, the in situ synthesized CNTs on surfaces of Al flake powders d

Fig. 3 The morphologies of different Al powders, Al powders (5 g) in transparent bottles and illustrations of the B4C/Al composite powder compacting for composites: a PM (spherical, 45 μm), b PM (spherical, 10 μm), c flake PM (2 μm in thickness)

Fig. 4 The reinforcement distribution in the 32 vol.% B4C/Al composite powders and the extruded composites made by PM (spherical 45 μm), PM (spherical 10 μm) and flake PM (2 μm in thickness): a-c SEM images of the composite powders, d-f OM images of the extruded composites, g-i the interspace statistics of adjacent B4C particles in the extruded composites via OM image analyzer, and the theoretical interspace of 2.259 μm for 32 vol.% B4C (7 μm)/Al composites is also marked by red dashed line

Fig. 5 Laminated structure of flake PM produced Al2O3/Al composites a, CNTs/Al composites b

Fig. 6 OM images of B4C/Al a, B4C/Al (Al2O3) c composites, TEM images of the matrix of B4C/Al b, B4C/Al (Al2O3) d composites

Fig. 7 a The strengthening efficiency and tensile strength for CNT/Al composites fabricated by various methods [19], b tensile properties of 32 vol.% B4C/Al composites fabricated by flake PM and the commercial B4C/Al composites, manufactured by leading composite companies [12]

Fig. 8 EBSD maps of the disordered a, laminated b composites, the inset in the bottom right-hand corner is the {111} pole figure, ED, TD and ND represent the extrusion direction, transverse direction and normal direction, respectively. Schmid factors of a c, b d in the ED

Fig. 9 a An equivalent plastic strain distribution at a tensile strain of 0.012 and a powder thickness of 500 nm, b maximum equivalent plastic strain as a function of tensile strain, c fracture surfaces of Al2O3/Al nano laminated composites

Fig. 10 TEM images of the B4C/Al (Al2O3) during in situ tensile test before tensile test a, after tensile test at the strain of ~0.005 b