Understanding the deformed microstructure of cold-rolled IF and LC steel

This paper presents an overview of a series of investigations of the microstructure and texture of cold-rolled IF and LC steel. The investigations made extensive use of orientation mapping using electron backscattered diffraction (EBSD) in a field emission gun scanning electron microscope (FEG-SEM). The effect of grain boundaries on the deformed microstructure was examined by comparing the textures of regions near grain boundaries and in the interiors of grains.  A general weakening of the texture, but a strengthening of the {OOI}<110> component, occurs in the vicinity of grain boundaries. Misorientation angle and axis distributions were used to characterise the fragmentation of grains belonging to different orientation classes. The influence of carbon on the deformed microstructure and nucleation during recrystallization was clarified by examining the microstructures of LC and IF steels during rolling and annealing. Theresults of the investigations emphasize the important role of shear banding in determining the fragmentation behaviour of ND-fibre grains and the orientations of viable recrystallization nuclei within the deformed microstructure

Microstructural features of rolled mg-3Al-1Zn

The microstructures of hot- and cold-rolled Mg-3Al-1Zn (AZ31) are examined using scanning electron and optical microscopy. It is shown that the microstructures following multipass hot rolling and annealing are more uniform than those formed by heavy single pass rolling and annealing. The importance of twins in producing intragranular recrystallization is evident, although the most dominant nucleation site is grain boundaries. The cold-rolled structure after a rolling reduction of 15 pct is dominated by the presence of deformation twins. Twin trace analysis suggests that approximately two thirds of the twins are a form of &ldquo;c-axis compression&rdquo; twin. A number of &ldquo;c-axis tension&rdquo; twins were also observed and additional in-situ scanning electron microscopy experiments were performed to confirm earlier observations that suggest these twins can form after deformation, during unloading. <br /

Expecting some action:Predictive processing and the construction of conscious experience

Predictive processing has begun to offer new insights into the nature of conscious experience—but the link is not straightforward. A wide variety of systems may be described as predictive machines, raising the question: what differentiates those for which it makes sense to talk about conscious experience? One possible answer lies in the involvement of a higher-order form of prediction error, termed expected free energy. In this paper we explore under what conditions the minimization of this new quantity might underpin conscious experience. Our suggestion is that the minimisation of Expected Free Energy is not in itself sufficient for the occurrence of conscious experience. Instead, it is relevant only insofar as it helps deliver what Ward et al. (2011) have previously described as a sense of our own poise over an action space. Perceptual experience, we will argue, is nothing other than the process that puts current actions in contact with goals and intentions, enabling some creatures to know the space of options that their current situation makes available. This proposal fits with recent work suggesting a deep link between conscious contents and contents computed at an ‘intermediate’ level of processing, apt for controlling action.</p

The influence of solute carbon in cold-rolled steels on shear band formation and recrystallization texture

Two experiments were conducted to clarify the roles of grain size, solute carbon and strain in determining the recrystallization textures of cold-rolled and annealed steels. In the first experiment, samples of coarse-grained low-carbon (LC) and interstitial-free (IF) steels were cold-rolled to a 75% reduction in thickness. One sample from each steel was polished and cold-rolled an additional 5%, while the remaining samples were annealed for various times at 650&deg;C. In the second experiment, three samples from a commercial LC steel sheet were rolled 70% at 300&deg;C. Two of the samples were given a further rolling reduction of 5% of the original thickness, with one of the samples being given this additional reduction at 300&deg;C and the other at room temperature. Goss recrystallization textures are strengthened by coarse initial grain sizes, the presence of solute carbon and rolling at a temperature where dynamic strain ageing occurs, but are weakened by additional rolling beyond a reduction of 70%, especially when this extra rolling is conducted at a temperature where dynamic strain ageing does not occur. Characterization of key features of the deformed and recrystallized steels using optical microscopy, scanning electron microscopy (SEM) and electron back-scatter diffraction (EBSD) supports a rationale for these effects based on the repeated activation and deactivation of shear bands and the influence of solute carbon and dynamic strain ageing on the operating life of the bands and the accumulation of strain within them