Brass-type shear bands and their influence on texture formation

Paul, H.; Morawiec, Adam; Piątkowski, Andrzej; Bouzy, Emmanuel; Fundenberger, Jean-Jacques

doi:10.1007/s11661-004-0283-5

Cited by 80 publications

(82 citation statements)

References 32 publications

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“…This brings the traces of the grain boundaries closer to the shear plane, as observed earlier for twinned structures of different fcc metals, e.g. [17][18][19]22,23]. The orientation maps measured within the areas of both families of MSBs (Figs.…”

Section: Microstructural Changes As Results Of Msb Formationsupporting

confidence: 64%

“…whether or not the shears occur in fcc metals on {111}-type planes and along <110> -type directions , e.g. [6,8,[17][18][19]. It is also unclear how the onset of unstable flow depends on the material history and how the internal texture of the SBs influences the global deformation texture?, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…(i) Shear bands are not observed in microstructures dominated by equiaxed dislocation cells and near isotropic properties [22]. (ii) Shear banding is preceded by the formation of essentially planar obstacles to homogeneous dislocation glide [7][8][9][10][11][17][18][19]. (iii) Two groups of SBs can be distinguished according to the SFE.…”

Section: Introductionmentioning

confidence: 99%

“…In metals with a low SFE, brass-type SBs can be readily observed after medium deformations, e.g. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. They develop within the microstructures characterized by thin twin-matrix lamellae.…”

Section: Introductionmentioning

confidence: 99%

“…[24,25] and EBSD technique, e.g. [11,[17][18][19]. However, in polycrystalline metals the situation can be quite complicated.…”

Section: Introductionmentioning

confidence: 99%

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Deformation Microstructure And Texture Transformations In FCC Metals Of Medium-To-High Stacking Fault Energy: Critical Role Of Micro- And Macro-Scale Shear Bands

Paul¹,

Miszczyk²

2015

Archives of Metallurgy and Materials

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Microstructure and texture development in medium-to-high stacking fault energy face centred cubic metals were investigated in order to examine the role of lattice re-orientation on slip propagation across grain boundaries and to characterize the influence of micro-and macro-scale copper-type shear bands on textural changes at large deformations. Polycrystalline pure copper (fine -and coarse -grained) and fine-grained AA1050 alloy were deformed in plane strain compression at room temperature to form two sets of well-defined macroscopic shear bands. The deformation-induced sub-structures and local changes in crystallographic orientations were investigated mostly by scanning electron microscopy equipped with high resolution electron backscattered facility. In all the deformed grains within macro-shear bands a strong tendency to strain-induced re-orientation was observed. The flat, strongly deformed grains exhibited a deflection within narrow areas. The latter increased the layers' inclination with respect to ED and led to kink-type bands, which are the precursors of MSBs. The mechanism of macro-/ micro-shear bands formation is strictly crystallographic since in all the areas of the sheared zone, the crystal lattice rotated such that one of the {111} slip planes became nearly parallel to the shear plane and the <011> direction became parallel to the direction of maximum shear. This strain-induced crystal lattice rotation led to the formation of specific macro-/ micro-shear bands components that facilitated slip propagation across the grain boundaries without any visible variation in the slip direction.Keywords: Shear bands, Texture, SEM/EBSD, Copper, AA1050 alloy, Plane strain compression W pracy badano zmiany strukturalne i teksturowe w metalach o sieci regularnej ściennie centrowanej związane z lokalną re--orientacją sieci krystalicznej wynikającą z formowania się mikro-i makro-pasm ścinania. Analizowano polikrystaliczne próbki miedzi oraz aluminium o czystości technicznej (stop AA1050) odkształcane w temperaturze otoczenia w próbie nieswobodnego ściskania do zakresu odkształceń, w których następuje wyraźne uformowanie się dwóch rodzin makroskopowych pasm ścinania. W badaniach wykorzystano skaningowy mikroskop elektronowy wyposażony w system automatycznego pomiaru orientacji lokalnych. Zaobserwowano, że w ziarnach umiejscowionych w obszarze makroskopowych pasm ścinania występuje ściśle zdefiniowana tendencja rotacji sieci krystalicznej, w wyniku której jedna z płaszczyzn typu {111} przyjmuje położenie zbliżone do położenia płaszczyzny ścinania, a jeden z kierunków typu <110> (lub <112> ) wykazuje tendencję do sytuowania się równolegle do kierunku ścinania. Obserwowana w obszarze wnętrza pasm ścinania rotacja prowadzi do uformowania się specyficznej (mikro)tekstury, która umożliwia propagację poślizgów poprzez granice ziaren bez 'istotnej' zmiany kierunku ścinania.

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Section: Microstructural Changes As Results Of Msb Formationsupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…[24,25] and EBSD technique, e.g. [11,[17][18][19]. However, in polycrystalline metals the situation can be quite complicated.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Deformation Microstructure And Texture Transformations In FCC Metals Of Medium-To-High Stacking Fault Energy: Critical Role Of Micro- And Macro-Scale Shear Bands

Paul¹,

Miszczyk²

2015

Archives of Metallurgy and Materials

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Orientation Design for Enhancing Deformation Twinning in Cu Single Crystal Subjected to Equal Channel Angular Pressing

Han¹,

Sheng²,

Huang³

et al. 2008

Adv Eng Mater

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Slip and twinning are two major mechanisms in plastic deformation of crystalline materials; however, twinning is extremely difficult to occur in face‐centered‐cubic crystals under conventional conditions. The authors show that twinning becomes an active deformation mode in copper single crystal when subjected to equal channel angular pressing at room temperature. In particular, the observations revealed that deformation twinning became more active in the copper single crystal having a proper crystallographic orientation.

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TEM Orientation Imaging in Characterization of Texture Changes in FCC Metals

Paul

2010

Adv Eng Mater

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It has been frequently shown that the application of electron backscattered diffraction (EBSD) and high-resolution scanning electron microscopy (SEM) to structure and texture analyses of cold-deformed materials gives reasonable results only up to moderate strains ($1.5). In the case of higher deformations, especially for low-stacking-fault-energy (SFE) metals, the resolution of EBSD is not always sufficient. The application of systems of local orientation measurements based on transmission electron microscopy (TEM) is one of the ways towards the solution of the problem. Because of the good spatial resolution (which is usually estimated to be about 10nm [1] ) and the accuracy of the orientation determination (better than 0.18), local-orientation measurements with TEM appear to be a suitable method for the investigation of fine-grained (and/or highly deformed) structures.The determination of the orientation using TEM has an outstanding advantage over SEM/EBSD because the orientation distribution and bright-field image of the microstructure can be recorded at the same time with a high spatial resolution, which enables a direct comparison of the orientation distribution with the dislocation structure. This is particularly important for the analysis of very-early stages of recrystallization.Recent studies leading to the design of a fully automatic TEM system are focused on automatic indexation of transmission Kikuchi bands, for example ref. [2][3][4] However, the application of fully automatic indexing in TEM is more difficult than in the case of SEM mainly due to the smaller acquisition angle and higher indices of the diffraction planes, but also because of the poorer quality of the diffraction patterns. The latter 'parameter' depends not only on the dislocation density (surface strains) but also the specimen thickness. Moreover, according to Schwarzer, [2] the accuracy of the system by the use of automatic indexing was proved up to 0.58, whereas it is only 0.18 by manual indexing. Thus manual indexing is still widely used for accurate determination of crystallographic orientations.They are other problems related to the acquisition time and long-range drift. The pattern acquisition is still the main factor determining the time needed for map creation (usually $25-30 patterns per minute). Additionally, the intensities in the original patterns significantly decrease with the distance from the center of the image. The systems deal with this problem by taking two pictures at different exposition times. [1,5] In order to avoid long-range drift, thermal stability of the microscope and the sample holder has to be achieved.The high precision of the determination of misorientations in TEM opens new possibilities for research on orientation relationships and subgrain characterization. This method was applied in the presented investigations to the crystallographic analysis of shear bands (SBs). Despite the fact that this phenomenon is an important feature of the microstructural behavior of face centered cubic (fcc) metals at la...

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Brass-type shear bands and their influence on texture formation

Cited by 80 publications

References 32 publications

Deformation Microstructure And Texture Transformations In FCC Metals Of Medium-To-High Stacking Fault Energy: Critical Role Of Micro- And Macro-Scale Shear Bands

Deformation Microstructure And Texture Transformations In FCC Metals Of Medium-To-High Stacking Fault Energy: Critical Role Of Micro- And Macro-Scale Shear Bands

Orientation Design for Enhancing Deformation Twinning in Cu Single Crystal Subjected to Equal Channel Angular Pressing

TEM Orientation Imaging in Characterization of Texture Changes in FCC Metals

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