Developing high toughness laminated HfB₂-SiC ceramics with ductile Nb interlayer

Herein, laminated HfB₂-SiC/Nb ceramic with multi-layered structure was synthesized via tape casting and spark plasma sintering. Despite minor loss in strength of laminated HfB₂-SiC/Nb ceramics (447 ± 12 MPa) compared with that of monolithic HfB₂-SiC ceramics (470 ± 16 MPa) following the introduction of ductile weak Nb interlayer, fracture toughness of laminated ceramics reached 14.22 ± 0.6 MPa m^1/2, showing an improvement of ∼129% in comparison with monolithic ceramics (6.11 ± 0.3 MPa m^1/2). Cooperative toughening mechanisms of crack behavior (deflection and delamination) and plastic deformation (dimples and tear ridges) led to the improvement in toughness. This research provides novel strategy for the development of heterogeneous ceramic–metal layered composites with superior fracture toughness.