Work-hardening/softening behaviour of b.c.c. polycrystals during changing strain:

Deformation-induced orientation spread in individual bulk grains of an interstitial-free steel

“…Substantial orientation changes have previously been correlated with changes in the identity of the neighbouring grains along the length of a grain as observed by 3DEBSD [44]. This general conclusion is also in agreement with the findings in both body-centred [45][46][47] and face-centred [48][49][50][51][52] cubic materials of similar alignment of dislocation boundaries in grains of similar orientation. The similar alignment was further linked to similarities in the activated slip systems [53] and correlated with changes in the flow stress upon a strain path change [54,55].…”

Crystal Plasticity Finite-element Simulation on Development of Dislocation Structures in BCC Ferritic Single Crystals

“…This assumption is utilized in Peeters model probably because in most cases only one or two sets of CBBs develop at the same time experimentally. [26][27][28][29][30][31][32][33][34][35] Rauch and Schmitt 38) also reported that during simple shear of a polycrystalline mild steel sheet one set of CBBs developed in most of the grains. In fact, to the best of our knowledge, a case where three or larger sets of CBBs develop at the same time has not been reported.…”

“…It should be noted that the materials utilized were different depending on the literature: an interstitial free steel sheet was used in the studies by Peeters and his co-workers, 30,31) whereas ferritic single crystals are assumed 34,35) in the present study. This difference in materials could also affect development of CBBs along the {112} planes.…”

“…Nesterova et al 29) examined microstructure evolution under different strain paths in an interstitial free steel sheet and reported that developed dislocation structures could be classified into six categories depending on strain path and crystallographic orientation. On the basis of the observed correlation between dislocation structure and work-hardening, Peeters et al 30,31) proposed a dislocation-based crystal plasticity model (Peeters model) in which the development of cell-block boundaries (CBBs) and its effect on work-hardening were formulated directly. This model enabled the accurate predictions of stress-strain curves and development of CBBs in a polycrystalline interstitial free steel sheet during various monotonic and twostage strain paths.…”

“…Because it is understood that CBBs in bcc crystals develop parallel to planes of highest slip activity, 31,32) this observation indicates that the activity of the {112} slip systems would be intrinsically smaller than that of the {110} slip systems, and moreover, the effect of the {112} slip activity on the workhardening is small. On the other hand, there are in fact some literatures that reported the development of CBBs parallel to the {112} planes.…”