Mechanical Performance of 3Y-TZP/Ni Composites: Tensile, Bending, and Uniaxial Fatigue Tests

Dense 3-mol%-yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP/Ni) homogeneous composites were prepared by a wet-processing route with metal concentration ranging from 0 to 40 vol%. Cyclic fatigue stress/life, tensile and bending strength, and fracture toughness were investigated in 3Y-TZP monolithic samples and 3Y-TZP/Ni composites. It was found that the addition of Ni particles to the 3Y-TZP matrix produced an embrittlement effect in the composites, decreasing the mechanical properties. This fact was attributed to the weak bonding between the Ni and 3Y-TZP particles in samples sintered in a reductive atmosphere. Additionally, the presence of Ni particles decreases the cyclic tensile fatigue of the composites probably by an environmentally assisted slow crack growth.