Effect of an electric field on the plastic deformation and fracture of polycrystalline NaCl

Yang, Dongmei; Conrad, H.

doi:10.1016/s0921-5093(96)10846-7

Cited by 15 publications

(8 citation statements)

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“…Many interesting results are observed in this field. The reports show that most of those researches focus on solid-state materials [1][2][3][4][5][6][7][8]. Some of them deal with solidification of aluminum alloy with AC, DC, high current density electropulsing, and magnetic field [9][10][11][12], and electric current refining microstructure of Pb-Sn eutectic [13].…”

Section: Introductionmentioning

confidence: 99%

The solidification of Al–Cu binary eutectic alloy with electric fields

Liu

Zhao

Wang

et al. 2004

Journal of Crystal Growth

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Section: Introductionmentioning

confidence: 99%

The solidification of Al–Cu binary eutectic alloy with electric fields

Liu

Zhao

Wang

et al. 2004

Journal of Crystal Growth

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“…The density of the as-sintered specimens the ductility of polycrystalline NaCl [8][9][10][11][12][13] and fine-grained ranged from 97 to 98 pct and the mean linear intercept 3Y-TZP (yttria-stabilized tetragonal zirconia polycrysgrain size, d o , from 1.4 to 2.9 m, increasing with sintering tals). [14] It also retarded grain growth in these materials.…”

Section: Introductionmentioning

confidence: 99%

Influence of an electric field on the plastic deformation of fine-grained Al2O3

Campbell

Fahmy

Conrad

1999

Metall Mater Trans A

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The influence of an electric field E ϭ 300 V/cm on the plastic deformation at 1450 ЊC to 1600 ЊC of fine-grained alumina with ϳ300 ppm MgO and d o ϭ 1.4 to 2.5 m was investigated. After removal of the effect of Joule heating, the field reduced the flow stress by ϳ4 MPa relatively independent of temperature, representing a 25 to 70 pct reduction in the flow stress. The field had no effect on the stress exponent n ϭ 2.2, nor on the grain size exponent p ϭ 1.9. It did however have an appreciable effect on the combined constant AD o of the Weertman-Dorn equation and the activation energy Q. The latter increased from 492 kJ/mole without the field (typically that for Al 3ϩ ion lattice diffusion) to 880 to 1070 kJ/mole with the field, which is more typical of sub-boundary or grain boundary diffusion of either Al 3ϩ or O 2Ϫ -ions in alumina. It therefore appears that the field changed the ratecontrolling, grain boundary sliding accommodation mechanism from the lattice diffusion of Al 3ϩ ions to either sub-boundary or grain boundary diffusion of Al 3ϩ or O 2Ϫ -ions. The electric field caused isotropic swelling of the specimen when applied for an extended period of time without application of stress. Pores responsible for the swelling occurred along the grain boundaries. They may have resulted from electrotransport of Al 3ϩ ions, leaving behind an Al-deficient layer from which free oxygen bubbles formed along the grain boundaries. Electric field-enhanced gas reactions at the pores may have also contributed to the swelling. It is proposed that swelling due to electrotransport may possibly be avoided by the addition of solutes, which increase the electronic or oxygen ion conductivity transference numbers compared to the aluminum ions.

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“…I N PRIOR work by the authors, 1 it was found that an electric men. The more complex electrode configurations D and E repfield of 0.1 MV/m reduced by ϳ50% the flow and fracture resented combinations consisting of electrodes at one or both stresses of cast polycrystalline (2 mm grain size) NaCl in comends of the specimen and an external cylindrical electrode (6 cm pression at room temperature.…”

mentioning

confidence: 98%

“…(3) Cast polycrystalline (2 mm average grain size) specimens (2 cm diam ϫ 5 cm high) of 99.9% NaCl were prepared in the manner described in Ref. 1. Their microstructure consisted of where K is the relative dielectric permittivity (ϭ5.90 for NaCl) a central core (ϳ7 mm diam) of a relatively fine grain size and R 1 , R 2 , R 3 , and R 4 are shown in Fig.…”

mentioning

confidence: 99%

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Electroplastic Effect in Cast Polycrystalline NaCl with Various Orientations of the Electric Field

Yang

Conrad

1997

Journal of the American Ceramic Society

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The influence of various orientations and configurations offlat with SiC abrasion papers down to 1000 grit, as were also the surfaces of the holes drilled in the specimens for configuraan electric field on the flow and fracture stresses in compression of cast polycrystalline NaCl was determined at room tions B-a, and B-b. The specimens were then polished in distemperature. An electric field of }0.1 MV/m reduced the tilled water to give smooth internal and external surfaces. flow and fracture stresses by }50%, relatively independentThe external electrodes for all configurations were of stainof the orientation of the field. This field is one to two orders less steel sheet. For configuration A in Fig. 1, 6.5 cm diam of magnitude lower than those previously reported to stainless steel sheets were placed at the top and bottom ends of enhance {110} ͗110͘ dislocation motion in NaCl single crysthe compression specimen and connected to the positive and tals. It is concluded that in the present tests on polycrystals negative terminals of the power supply. The geometry and the electric field enhanced cross slip. Several mechanisms dimensions pertaining to configurations B-a, B-b, and C are by which this might occur are proposed.shown in Fig. 2. The internal electrodes in B-a and B-b were a copper tube and wire, respectively. For configuration C, the two stainless steel sheet electrodes (4 cm ϫ 5 cm high) were placed I. Introduction parallel to, and equidistant from (2 cm), the cylindrical speci-I N PRIOR work by the authors, 1 it was found that an electric men. The more complex electrode configurations D and E repfield of 0.1 MV/m reduced by ϳ50% the flow and fracture resented combinations consisting of electrodes at one or both stresses of cast polycrystalline (2 mm grain size) NaCl in comends of the specimen and an external cylindrical electrode (6 cm pression at room temperature. These field strengths are one to diam). An example of the specimen arrangement during comtwo orders of magnitude lower than those which had been pression testing (that for electrode configuration C) is given in previously reported to enhance dislocation multiplication and Fig. 3. That for A was previously shown in Ref. 1. motion in halide single crystals. [2][3][4][5][6][7][8][9][10][11][12] It was proposed by the The electric field in the NaCl specimen for configuration A present authors that the reduction in the flow and fracture was taken to be stresses in the case of their polycrystals resulted from an E ϭ V 0 /h (1) enhancement of cross slip by the electric field.In the previous paper, 1 the electric field was applied along the where V 0 is the applied voltage and h the specimen height. The compression axis. In view of the relatively large effect of elecaverage field in the NaCl in the case of B-a and B-b was tric field that was observed, the present study was undertaken to determined from 13 determine whether similar behavior occurs with other orientations and configurations of the field. It was found that the(2) reductions in flow and fra...

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Effect of an electric field on the plastic deformation and fracture of polycrystalline NaCl

Cited by 15 publications

References 35 publications

The solidification of Al–Cu binary eutectic alloy with electric fields

The solidification of Al–Cu binary eutectic alloy with electric fields

Influence of an electric field on the plastic deformation of fine-grained Al2O3

Electroplastic Effect in Cast Polycrystalline NaCl with Various Orientations of the Electric Field

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