The incorporation of ambipolar diffusion in deformation mechanism maps for ceramics

Langdon, Terence G.; Mohamed, Farghalli A.

doi:10.1007/bf00541795

Cited by 38 publications

(8 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…• C and the applied stress of less than 100 MPa, [20][21][22][23] and the grain boundary sliding contributes dominantly to the plastic flow in polycrystalline Al 2 O 3 with a grain size of less than about 2 µm. [24][25][26][27] In our previous study, it has been revealed that a stress exponent n (inverse strain rate sensitivity) in fine-grained, single-phase Al 2 O 3 for high-temperature creep deformation is about 2, which indicates the creep deformation mechanism of interface reaction 28) or grain boundary sliding.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Chemical Bonding State on High-temperature Plastic Flow Behavior in Fine-grained, Polycrystalline Cation-doped Al2O3

et al. 2002

View full text Add to dashboard Cite

High-temperature plastic deformation characteristics such as flow stress and elongation to failure in polycrystalline Al 2 O 3 with an average grain size of about 1 µm is remarkably changed by the doping of 0.1 mol% YO 1.5 , SiO 2 , TiO 2 or ZrO 2 at 1400 • C under an initial strain rate of 1.2 × 10 −4 s −1 . The difference in the flow stress and the tensile ductility is considered to be originated from change in the grain boundary chemistry in Al 2 O 3 due to segregation of the dopant cation in the vicinity of the grain boundary. A change in the chemical bonding state in the cations-doped Al 2 O 3 is examined by first-principle molecular orbital calculations using DV-Xα method based on [Al 5 O 21 ] 27− cluster model. Chemical shift observed in electron energy-loss spectra (EELS) at the grain boundary due to the dopant segregation can be roughly reproduced by the molecular orbital calculations. A correlation is found between the flow stress and product of net charges of aluminum and oxygen ions. Moreover, the tensile elongation to failure seems to correlate with bond overlap population between Al and O. The change in the chemical bonding strength at the grain boundary must dominantly affect to the grain boundary diffusion and bond strength at the grain boundary, and thus seems to be an important factor to determine the plastic flow behavior in polycrystalline Al 2 O 3 .

show abstract

Section: Resultsmentioning

confidence: 99%

“…[20][21][22][23][24][25][26][27] The predominant deformation mechanism in Al 2 O 3 with a grain size of less than about 10 µm is grain boundary diffusion creep at temperatures of 1100-1400…”

Section: Resultsmentioning

confidence: 99%

Effect of Chemical Bonding State on High-temperature Plastic Flow Behavior in Fine-grained, Polycrystalline Cation-doped Al2O3

et al. 2002

View full text Add to dashboard Cite

show abstract

“…[9][10][11][12][13][14][15][16] The predominant deformation mechanism in Al 2 O 3 with the grain size of less than about 10 mm is grain boundary diffusion creep at temperatures of 1100-1400 C and under a stress of less than 100 MPa, [9][10][11][12] and the grain boundary sliding contributes dominantly to the creep deformation when the grain size is less than about 2 mm. [13][14][15][16] It has been reported that the creep deformation in fine-grained Al 2 O 3 with the average grain size of about 1 mm takes place by grain boundary sliding accommodated by grain boundary diffusion.…”

Section: Resultsmentioning

confidence: 99%

Improvement of High-temperature Creep Resistance in Polycrystalline Al2O3 by Cations Co-doping

et al. 2004

View full text Add to dashboard Cite

High-temperature creep resistance in cations co-doped polycrystalline Al 2 O 3 was examined by uniaxial compression creep test at 1250 C. The dopant oxides used in this study were 0.1 mol% of YO 1:5 , ZrO 2 , SrO, MgO and TiO 2 . The creep rate in Al 2 O 3 was significantly changed by cations co-doping. For instance, Zr/Y co-doping suppressed the creep rate in Al 2 O 3 by a factor of about 400. A high-resolution transmission electron microscopy (HREM) and nano-probe energy dispersive X-ray spectroscopy (EDS) analysis revealed that Y and Zr cations segregate along grain boundaries. The grain boundary diffusion in Al 2 O 3 was supposed to be retarded by the segregation of Y and Zr cations. A firstprinciple molecular orbital calculation was made for cations co-doped Al 2 O 3 and cation singly doped Al 2 O 3 model cluster. The creep rate was correlated with the value of net charge in oxygen anion. The net charge of oxygen anion was one of the most important factors to determine the creep resistance in Al 2 O 3 .

show abstract

“…4. Generally, the stress dependence of the strain rate (stress exponent: n) was evaluated to infer the mechanical response for high-temperature deformation using the following relation [14]:…”

Section: Resultsmentioning

confidence: 99%

Accumulation of plastic strain in Zircaloy-4 at low homologous temperature

Matsunaga

Satoh

Abe

2015

Journal of Nuclear Materials

View full text Add to dashboard Cite

a b s t r a c tTime-dependent strain accumulation in Zircaloy-4 was evaluated at 294 K, i.e., homologous temperature (T/T m , where T m is the melting temperature) of 0.14, to ascertain the mechanical response in fuel cladding material, even at the time of storage. Although diffusion processes are suppressed, considerable strain accumulation was observed at less than 0.2% offset stress. Transmission electron microscopy and electron backscattered diffraction analyses were used to investigate the dominant microstructural mechanism. Results showed that the heterogeneous dislocation structure generated strain accumulation, where straightly aligned dislocation arrays on the prismatic plane move freely and few deformation twins were formed in the grain interior. Furthermore, few dislocation tangles were observed because the slip systems were limited to one. Therefore, Zircaloy-4 shows weak work-hardening at the low homologous temperature because of the fewer interactions among dislocations, leading to unexpected strain accumulation under constant load conditions.

show abstract

The incorporation of ambipolar diffusion in deformation mechanism maps for ceramics

Cited by 38 publications

References 22 publications

Effect of Chemical Bonding State on High-temperature Plastic Flow Behavior in Fine-grained, Polycrystalline Cation-doped Al<SUB>2</SUB>O<SUB>3</SUB>

Effect of Chemical Bonding State on High-temperature Plastic Flow Behavior in Fine-grained, Polycrystalline Cation-doped Al<SUB>2</SUB>O<SUB>3</SUB>

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

Accumulation of plastic strain in Zircaloy-4 at low homologous temperature

Contact Info

Product

Resources

About