Microstructural Evolution During Hot Rolling of an AZ31 Mg Alloy

The microstructural evolution of a AZ31 Mg alloy during hot rolling has been investigated using optical microscopy and texture (macro and micro) analysis as the main characterization tools. In particular, the differences between the microstructure obtained by unidirectional rolling (UR) and cross rolling (CR) are studied. Significant twinning activity is observed in both cases. Additionally, after cross rolling, a rather heterogeneous microstructure develops, with scattered regions populated by very fine grains. The strong basal fiber texture of the as-received material remains present after both hot rolling schemes. The imposibility to obtain accurate EBSD measurements within the twinned regions suggests that significant localized deformation takes place in those areas. Thus, due to the increase in the local strain energy, these regions become preferential sites for nucleation of recrystallization.Peer reviewe

Methodology for the Evaluation of Forecast Reliability of Production Planning Systems

AbstractThe high dynamics of markets are only one reason for the increasing complexity of production planning and control. To handle this complexity manufacturing companies have implemented IT systems to support decision-making in detailed scheduling processes. However, applied IT systems often do not provide a reliable forecast of delivery dates, because the planning models are implemented uniquely and have never been adapted due to changes in the production system. This paper presents an approach to verify the forecast reliability of detailed planning systems by identifying deviations between the predicted production schedule, determined by the IT system, and the observed production processes in reality. The paper introduces the reasons for deviations and explains how they can be determined. The approach represents how categorical and continuous verification methods can be applied to identify the described deviations. Depending on the determined deviations the forecast quality index of detailed planning systems is developed. Besides the assessment of the forecast quality the reasons for deviations are of interest to production planners. Identified reasons are the starting point for adaptions in planning models to enable a reliable forecast of re-configurable production planning systems in the future