Grain Boundaries in High Temperature Deformation of Yttria and Magnesia Co-Doped Alumina

Abstract

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Structure and chemistry of grain boundaries in yttria doped aluminas

“…In this last case, which occurs in the general GB, it is assumed that yttrium has been attracted by the strain field of dislocations that are then stabilized by segregated species. This result justifies the proposed strengthening mechanisms that accounts for the modification of the fine-grained alumina superplastic behavior when yttrium is added [17,18]. Indeed, dislocations are present in general GB's after creep in agreement with the assumption of lower GB diffusion that results in a decrease in GB dislocation accommodation processes.…”

“…This may be interpreted on the basis of an intergranular dislocation creep model [7,16]. Codoping with yttrium leads to a sharp decrease in the initial deformation rate [13]; it has been suggested that yttrium modifies the role of GB's as sources and sinks for lattice dislocations [17] [19]. Thus, we have developped a microstructural study of intergranular segregation of yttrium with two aims: on one hand to more thoroughly understand yttrium effect on the creep deformation of alumina, on the other hand to define the parameters of the relationship between GB structure and segregation.…”

Relationship between microstructure and abrasive wear resistance of Al2O3–FeAl2O4 nanocomposites produced via solid-state precipitation

“…13 This is presumed to be because Y 2 O 3 is known to reduce the grain boundary diffusivity of alumina. [17][18][19] In contrast to the coarser intergranular particles, the intragranular FeAl 2 O 4 particles were in the nanosized regime (<100 nm) even on aging for 20 h at 1450 • C ( Fig. 1a and c).…”

Improvement of High-temperature Creep Resistance in Polycrystalline Al<SUB>2</SUB>O<SUB>3</SUB> by Cations Co-doping

“…4) The creep resistance has also been examined in cations codoped Al 2 O 3 . [5][6][7] For instance, it has been reported that Nd/ Zr co-doped Al 2 O 3 exhibited superior creep resistance than Nd or Zr singly doped Al 2 O 3 . 7) However, the co-doping effect has not been systematically examined, and the origin of the effect of cations co-doping on the creep resistance in Al 2 O 3 has not been clarified yet.…”