Toughening mechanisms in YTa3O9 perovskite ceramics with domain walls

First-principles calculations predict the quasi-static mechanical properties of the YTa 3 O 9 material. Orthorhombic phase YTa 3 O 9 ceramics, exhibiting a ferroelastic domain structure with two types of domains separated by 90° orientation differences, are synthesized by solid-state reaction. The mechanical properties and stress-strain behavior of the ceramics under various uniaxial compression loads are investigated through nanoindentation, Vickers indentation and universal testing machine equipped with digital image technology. The toughening mechanism is primarily governed by the layered structure, which promotes crack bifurcation, deflection, and bridging, together with the complex crack-propagation processes controlled by ferroelastic domain switching. Moreover, the stress–strain responses under various loading conditions and during cyclic compression exhibit the characteristic hysteresis of ferroelastic materials. No macroscopic fracture is observed during compression, owing to the increased energy barrier for crack propagation provided by the layered architecture and domain-switching mechanisms.