|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Mechanical Behavior at the Nanoscale IV
||Understanding Effect of Grain Boundaries on Deformation and Strength of Yttria-stabilized Tetragonal Zirconia Bicrystals
||Ning Zhang, Mohsen Asle Zaeem
|On-Site Speaker (Planned)
Grain boundary (GB) is one of the important structural features of polycrystalline materials in terms of determining their mechanical properties. By using molecular dynamics (MD) simulations, the effect of GBs on phase transformation and dislocation migration behaviors, and consequently on mechanical properties of bi-crystalline yttria-stabilized tetragonal zirconia (YSTZ) nanopillars are systematically investigated. Based on the identified crystallographic orientation effect on dominant plastic deformation mechanisms of YSTZ, six distinct bicrystals with symmetric or asymmetric GBs are generated and subjected to uniaxial compressive loading. Simulation results show that in most cases GBs act as nucleation sites for phase transformation and amorphous phase formation. Dislocation nucleation becomes least competitive and thus is impeded. Hence, it leads to a decrease of strength and results in a ductile behavior of bicrystals. However, as the loading is applied along a GB direction, interestingly, an increase of strength is observed.
||Planned: Supplemental Proceedings volume