Fig. 6: Simultaneous stiffness and toughness of gradient architecture.

a, b Gradual modulus decreases and increases in the L → S gradient architecture from coarse to fine grains and the S → L gradient architecture from fine to coarse grains, respectively. c, d Large field tomographic images of (i) post-fracture surface, (ii) crack profile, and (iii) fiber orientation/distributions in the L → S and S → L gradient architecture. e L-D curves of the L → S and S → L gradient architectures showing increased fracture toughness compared to the initial case of monotonically assembled architectures. f R-curves of the L → S and S → L gradient architectures showing J-shaped and Γ shaped curves, respectively. Detailed tomographic images of the fracture surface and thickness are presented in Suppl. Fig. 9. Source data are provided as a Source Data file.