Microstructure and mechanical behavior of TiO 2 ‐MnO‐doped alumina/alumina laminates

Tapes of TiO 2 ‐MnO‐doped alumina (d‐Al 2 O 3 ) and pure alumina (Al 2 O 3 ) were shaped via tape casting. Laminates with three different layer numbers and respective thicknesses were produced and sintered at 1200°C. The microstructure and mechanical behavior of laminates were investigated and compared to the respective monolithic references (d‐Al 2 O 3 and Al 2 O 3 ). The use of dopants in alumina decreased the initial sintering temperature, leading to higher densification at 1200°C (~98% theoretical density (TD)) when compared to Al 2 O 3 (~73% TD). The higher density was reflected in a higher Young's modulus and hardness for doped alumina. A region of diffusion of dopants in pure alumina layers was observed along the interface with doped layers. The mechanical strength of d‐Al 2 O 3 samples sintered at 1200°C was not statistically different from Al 2 O 3 samples sintered at 1350°C. The strength of laminates composed of doped layers with undoped, porous interlayers did not change. Nevertheless, as the thickness of these porous interlayers increases, a loss of strength was observed. Monolithic references showed constant values of fracture toughness (K IC ), ~2 MPa·m 1/2 , and linear crack path. On the other hand, K IC of laminates increases when the crack propagates from weak Al 2 O 3 layers to dense d‐Al 2 O 3 layers.