TEM Characterization of Lattice Defects Associated with Deformation and Fracture in α-Al2O3

Abstract

AbstractAlumina (α-Al2O3) is one of the representative structural ceramics. To understand its mechanical responses, the lattice defect behavior of alumina has been investigated by transmission electron microscopy (TEM) for many years. In this report, we review our recent research progress on TEM structural analysis of lattice defects in alumina. In the first half, the core atomic structure and dissociation reaction of b = $$1/3<11\bar{2}0>$$ 1 / 3 < 11 2 ¯ 0 > , $$<1\bar{1}00>$$ < 1 1 ¯ 00 > , and $$1/3<\bar{1}101>$$ 1 / 3 < 1 ¯ 101 > dislocations formed in low-angle grain boundaries are investigated by atomic-resolution TEM observations. Based on experimental results, the slip deformation behavior associated with those dislocations is discussed. In the second half, the formation of $$1/3<11\bar{2}0>$$ 1 / 3 < 11 2 ¯ 0 > dislocations and fracture of Zr-doped ∑13 grain boundary of alumina are observed by in situ TEM nanoindentation. Furthermore, these indented samples were observed by atomic-resolution scanning TEM. The mechanisms of the deformation and fracture phenomena are discussed in detail.