Competing Mechanisms between Dislocation and Phase Transformation in Plastic Deformation of Single Crystalline Yttria-Stabilized Tetragonal Zirconia Nanopillars

摘要

Molecular dynamics (MD) is employed to investigate the plastic deformationmechanisms of single crystalline yttria-stabilized tetragonal zirconia (YSTZ)nanopillars under uniaxial compression. Simulation results show that thenanoscale plastic deformation of YSTZ is strongly dependent on thecrystallographic orientation of zirconia nanopillars. For the first time, theexperimental explored tetragonal to monoclinic phase transformation isreproduced by MD simulations in some particular loading directions. Threedistinct mechanisms of dislocation, phase transformation, and a combination ofdislocation and phase transformation are identified when applying compressiveloading along different directions. The strength of zirconia nanopillarsexhibits a sensitive behavior depending on the failure mechanisms, such thatthe dislocation-mediated deformation leads to the lowest strength, while thephase transformation-dominated deformation results in the highest strength.