Effects of Crystal Orientation and Pre-existing Defects on Nanoscale Mechanical Properties of Yttria-Stabilized Tetragonal Zirconia Thin Films

N Zhang and MA Zaeem, JOM, 71, 3869-3875 (2019).

DOI: 10.1007/s11837-019-03725-z

Effects of crystal orientation and pre-existing defects on tensile properties of yttria-stabilized tetragonal zirconia (YSTZ) thin films are investigated by large-scale molecular dynamics simulations. The tensile strength and strain show clear orientation dependence. Under uniaxial tensile loading, the YSTZ thin films are found to fail through fracture along 110 cleavage planes. dislocations are observed to form in the 100-, 010- and 001-oriented models. Besides, the 110 cleavage planes are noticed to be rough, twisted and tangled around the center of the 100- and 001-oriented films, which is responsible for large strains at tensile strength. The simulated Young's modulus and tensile strength are comparable to the experimental and first principle values. Overall, pre-existing defects could change the fracture pathway and negatively affect the tensile strength and strain in most of the studied cases.

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