Multi-scale characterizations of shear localization in strip cast AA5754 aluminum alloy sheet

In the present study, multi-scale characterization of shear localization in strip cast AA5754 aluminum alloy sheet is presented. Strain mapping has been conducted at two levels. Full-field strain mapping based on digital image correlation method was used to explore the Portevin-Le Chatellier phenomenon. The results show that shear localization emerged following type-B PLC band propagation during deformation. Eventually one of these PLC bands interacts with the shear bands and leads to the final localized necking and failure of the material. In addition in-situ uniaxial tensile tests were conducted in a field-emission scanning electron microscope (FE-SEM) in order to reveal slip lines developed during deformation. By utilizing the SEM topography image correlation method, full-field in-situ strain mapping at the grain level is realized. The results show that local strain at this scale can reach the order of one and reveal how slip between grains becomes connected. Based on the above observations, we are able to identify the sequences of the events in the development of tensile instability of strip cast AA5754 aluminum alloy sheet.