Hsueh C.H.Becher P.F.CHUN-HWAY HSUEH2019-09-252019-09-25200510980121https://scholars.lib.ntu.edu.tw/handle/123456789/424914The segregation of dopants whose electric charge is different from that of the parent ions and the formation of a space-charge layer induce a local electric field in the grain-boundary region. Depending upon the valence and local electrostatic potential, the charge carriers controlling diffusional creep can be either accumulated or depleted in this space-charge layer, and the creep rate is enhanced or diminished accordingly. A model was recently developed to examine the effects of a segregation-induced local electric field on the lattice-diffusional creep of nanocrystalline ceramics for spherical grains. However, in order to obtain closed-form solutions, the grain size was assumed to be much greater than the width of the space-charge layer in the existing analysis. This assumption can become inappropriate for nanocrystalline materials as the grain size is reduced; thus, a numerical method is used in the present study to resolve the existing equations without that assumption. Using yttria tetragonal zirconia as an example, the difference between the existing approximate closed-form solutions and the present numerical results is shown to be significant when the grain size is less than 50 nm. ? 2005 The American Physical Society.journal article10.1103/PhysRevB.71.0141152-s2.0-17044425559https://www2.scopus.com/inward/record.uri?eid=2-s2.0-17044425559&doi=10.1103%2fPhysRevB.71.014115&partnerID=40&md5=aeb4bb22e440509d055d200638022890