Formation of Dillamore orientation during accumulative roll bonding of {001}^|^lang;100^|^rang; aluminum single crystal

Abstract

A {001} 100 oriented aluminum single crystal was deformed by nine cycles of accumulative roll bonding which corresponded to a total equivalent strain of ε=7.2. The formation of {4 4 11} 11 11 8 component in deformation texture was examined by using electron back-scatter diffraction method. The specimen processed by five cycles ARB (ε=4) developed four variants of {123} 634 orientation in the deformation texture. Between the five and nine cycles, the four variants of {123} 634 rotated toward {4 4 11} 11 11 8 and {112} 111 orientations. The specimen after the ninth cycle had a weak texture which was mainly composed of {4 4 11} 11 11 8 , {112} 111 and {123} 634 components. The results obtained in the present study indicate that {4 4 11} 11 11 8 and {112} 111 become the primary and secondary stable orientations in the specimens deformed by accumulative roll bonding to the extremely high strain. The occurrence of the cyclic ratcheting which was reported by Heason et al. was also investigated. The cyclic ratcheting, which causes the formation of {4 4 11} 11 11 8 in the center layer, did not have much effect on the {001} 100 oriented single crystal.

Stability of {4 4 11} ⟨11 11 8⟩ Orientation in a {123} ⟨634⟩ Aluminum Single Crystal Processed by Accumulative Roll Bonding

“…8) The area fraction of {001} ©110ª was 5.8% in the (213) (001) [100] single crystal, the crystal rotation from {001} ©110ª to D orientation hardly occurred. Thus, the formation of {001} ©110ª (or {116} ©331ª) orientation, especially when formed in the surface layer, is important for the occurrence of cyclic ratcheting, which depends on the initial crystal orientations.…”

“…In our previous studies, 7,8) (112) [11 1] and (001) [100] oriented aluminum single crystals were deformed up to a total reduction in thickness of 99.8% (an equivalent strain of 7.18) by conventional rolling and subsequent ARB. Both single crystals indicated that the resultant main texture components in the center layer were D {4 4 11} ©11 11 8ª orientation (Dillamore orientation).…”

“…In the (112) [11 1] single crystal, 7) the formation of D orientation was caused by the cyclic ratcheting reported by Heason et al 5) However, cyclic ratcheting barely occur in the (001) [100] single crystal. 8) Therefore, further ARB experiments using other single crystals with different initial orientations are required in order to have a better understanding of the occurrence of cyclic ratcheting.…”

Coupled effects of initial orientation scatter and grain-interaction to texture evolution: a crystal plasticity FE study

“…Plastic deformation induced crystallographic texture has been a subject of research for decades because of its consequences for the material properties and deformation behaviours [1][2][3]. Among the texture components, Cube {0 0 1}<1 0 0> is an considerably investigated orientation in FCC structured metals (e.g., [4][5][6][7][8][9][10][11][12][13][14]). It is accepted that this orientation is unstable under rolling or plane strain compression (PSC) process [4][5][6], since it locates in the 'divergent' region of Euler space.…”

“…For single crystal after a ~50% thickness reduction, crystallographic orientations mainly rotate about transverse direction (TD) for exact Cube [4,7,8] and also for the initial orientation rotated about TD by 5° (5TD) [9], but the rotation axis is not specific for initially spined around rolling direction (RD) at 5° (5RD) [10]. A small deviation angle of 1.5° led to an asymmetrical distribution of texture after a large reduction [11,12]. Small deviation angles in single crystals were chosen intendedly to study the stability of Cube orientation during deformation in Refs.…”