Follow-up research on differential regulation of intragranular/lamellar structures on mechanical properties in ZTA ceramics

Zirconia toughened alumina ceramics through a foam precursor approach exhibits exceptional mechanical properties which enables precise control of zirconia spatial distribution to overcome the traditional strength-toughness trade-off. Fundamentally different strengthening mechanisms are demonstrated through a contrast between the conventional intragranular ZrO₂ dispersion structure and the foam-derived lamellar structure. The fabrication of abrupt Al₂O₃/ZrO₂ interfaces with compressive strain via foam-derived lamellar structures induces local strain in alumina and lattice defects in ZrO₂. This suppresses intragranular ZrO₂ formation and enhances toughening through microcrack initiation or phase transformation mechanisms, but the connecting ZrO₂ weakens its hardness. The isotropic 0–3 type structure with intragranular ZrO₂ forming a semi-coherent structure due to stress relaxation. The dislocation arrays around intragranular zirconia can induce transgranular fracture. These findings establish a new paradigm for designing high-performance structural ceramics through microstructure optimization.