Deformation Texture Evolution of Low Carbon Steel with Heterogeneous Structure

Abstract

The present study examines deformation textures in low-carbon steel with microstructural heterogeneity. EBSD and XRD have been used in order to follow the evolution of the texture in relation with deformation evolution. The non-deformed material shows a {111} fibre texture (γ-fibre), with a main component {111} <112>. The deformation aptitude may be related for bcc metals to the evolution of this fibre texture component. To follow the evolution of the deformation textures, tensile tests were performed from 5% up to failure. During deformation, the {111} <110> deformation component sharpens. In the presence of this component in the non-deformed sheet, plastic flow is easy, while the grain reorientation from the initial orientation {111} <112> towards the bcc deformation orientation {111}<110> implies an important micro-constraint state, which is able to initiate cracking in the studied sheet during drawing. Heterogeneous structure that develops during deformation induces heterogeneous mechanical behaviour; noted this evolution is not predictable using global characterization techniques. The morphological analysis shows the micro-band presence. In a heterogeneous structure the risk of cracking seems to increase in the presence of small grains {111} <112 > clusters. The EBSD technique showed the adjustment of the grain orientation from the component {111} <112> towards the global deformation orientation {111} <110>. This process can explain the possibility of crack propagation in a globally ductile material characterized by a main component {111} <110>.