Making high-performance Al2O3-3YSZ ceramics with eutectic/ polycrystalline structure by hot-pressing eutectic powders

In this communication, the Al2O3-3YSZ ceramic (AYC) was prepared by hot -pressing the eutectic powders. A continuous transition from raw powders mixture to synthesized eutectic powders to sintered eutectic bulk was traced and investigated. The AYC well preserves the structure and phase composition of the original Al2O3-3YSZ eutectic powders (AYEP), which possess a eutectic/polycrystalline composite structure. The average interphase spacing of eutectic region in AYC reaches 106 nm. The strength, toughness, and hardness of AYC specimen are as high as 768 +/- 23 MPa, 8.17 +/- 0.30 MPa m1/2, and 19.04 +/- 0.45 GPa, which far surpasses other solidified and sintered Al2O3-based eutectic ceramics. The excellent mechanical properties can be attributed to the synergistic toughening mechanisms of intergranular/transgranular fracture, t -m phase transformation and residual stress. These results clearly demonstrate the feasibility of sintering eutectic powders method to fabricate Al2O3-based eutectic ceramics concurrent with fine structure and large dimension.