Equal channel angular extrusion of niobium single crystals

Sandim, Hugo Ricardo Zschommler; Bernardi, Heide Heloise; Verlinden, Bert; Raabe, Dierk

doi:10.1016/j.msea.2007.02.086

Cited by 36 publications

(21 citation statements)

References 27 publications

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“…The sample was processed at room temperature using the route B c , for more details about processing are given in refs. 23,24 . Table 1 As-pressed samples were cut out and annealed in vacuum from 400 o C (673 K) to 900 o C (1173 K) for 1 hour holding time at each temperature to evaluate their thermal stability.…”

Section: Methodsmentioning

confidence: 99%

“…HABs increase significantly with temperature during annealing when recrystallization occurs in a discontinuous manner 29 . The volume fraction of HABs in the as-deformed material is about 48% 24 . It is worth mentioning that this large density of high-angle boundaries contributes to an increase in the stored energy in the deformed state, providing an additional driving force for grain coarsening.…”

Section: Annealing Behaviormentioning

confidence: 99%

“…Details of the as-worked microstructure of this particular Nb single crystal are given in ref. 24 . Figure 1 shows the SEM micrograph of the cross section (TD-ND) of the as-worked material after 8 ECAP passes.…”

Section: Deformation Microstructurementioning

confidence: 99%

“…This microstructure results of pronounced refinement promoted by ECAP as a result of the progressive subdivision of the crystal and further boundary refinement [9][10][11]25 . The volume fraction of HABs in ECAP-processed Nb after 8 passes was 48% and the average linear intercept distance between HABs was 0.33 ± 0.03 µm, after a standard cleaning procedure to remove non-indexed points 24 . Etter et al 26 and Reihanian et al 27 have investigated the microstructure of high-purity polycrystalline copper and aluminum deformed by ECAP using the same route B c .…”

Section: Deformation Microstructurementioning

confidence: 99%

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Microstructural Stability of a Niobium Single Crystal Deformed by Equal Channel Angular Pressing

et al. 2017

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A [211]-oriented niobium single crystal was deformed by equal channel angular pressing (ECAP) at room temperature using the route B c to a total strain of 9.2. A sharp cube texture develops after ECAP processing. The deformed samples were annealed in vacuum from 400ºC (673 K) to 900ºC (1173 K) for 1 h to evaluate their microstructural stability. Scanning electron microscopy (SEM) was used to image the microstructures of as-deformed and annealed specimens. Electron backscatter diffraction (EBSD) was employed to determine the respective microtextures before and after annealing. Coarsening of the microstructure occurs at a maximum rate at 550ºC (823 K) due to discontinuous recrystallization. Normal grain growth replaces discontinuous recrystallization as the main coarsening mechanism above 700ºC (973 K).

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Section: Methodsmentioning

confidence: 99%

Section: Annealing Behaviormentioning

confidence: 99%

Section: Deformation Microstructurementioning

confidence: 99%

Section: Deformation Microstructurementioning

confidence: 99%

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Microstructural Stability of a Niobium Single Crystal Deformed by Equal Channel Angular Pressing

et al. 2017

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“…In this respect, pure BCC metals or interstitial-free (IF) metals should be used in order to clarify the microstructural development intrinsic to BCC structures. Although the literature on pure BCC or IF steels processed by ECAP has been reported [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32], there are still very limited papers examining the microstructural evolution quantitatively in particular, the initial stage where dislocation substructure transforms into network of low/high angle grain boundaries.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Development of Fe-20mass%Cr Alloys and Pure Copper Processed by Equal-Channel Angular Pressing

Rifai¹,

Haga²,

Miyamoto³

et al. 2013

MSA

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Microstructural development of ultra low C, N, Fe-Cr alloy and pure copper processed by equal-channel angular pressing (ECAP) have been examined focusing on the initial stage of the formation of ultrafine grain structure. Fe-Cr alloys were pressed at 423 K while pure copper at room temperature for 1 to 3 passes via the route Bc to compare at the equivalent homologous temperature. Microstructural evolutions were characterized by electron backscatter diffraction (EBSD) image and transmission electron microscopy (TEM). It was found that deformation structures were mostly deformation-induced subboundaries in both the materials after one pass, but the fraction of high-angle grain boundary became higher in the Fe-Cr alloys than in pure copper in subsequent passes by increasing misorientation of the boundaries. The more enhanced formation of high angle boundaries in Fe-Cr alloys was discussed in terms of the nature of crystal slip of FCC and BCC structures.

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A new generalized upper-bound solution for the ECAE process

Abrinia

Mirnia

2009

Int J Adv Manuf Technol

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A new generalized upper bound solution for the ECAE process is presented in this paper. Using mathematical definition of Bezier curves a streamline was formulated to define a generalized deforming region. Based on this deforming region a kinematically admissible velocity field was obtained from which upper bound solutions were computed. By changing 0 d v Initial velocity in deforming region on the entry discontinuity surface C Constant for the velocity field equations to be determined from the boundary conditions

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Equal channel angular extrusion of niobium single crystals

Cited by 36 publications

References 27 publications

Microstructural Stability of a Niobium Single Crystal Deformed by Equal Channel Angular Pressing

Microstructural Stability of a Niobium Single Crystal Deformed by Equal Channel Angular Pressing

Microstructural Development of Fe-20mass%Cr Alloys and Pure Copper Processed by Equal-Channel Angular Pressing

A new generalized upper-bound solution for the ECAE process

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