Crystallographically resolved damage initiation in advanced high strength steel

Recently, the third generation of advanced high strength steels (AHSSs) show promising properties for automotive applications. The improvement of macroscopic mechanical performance is not feasible without a deep understanding of the micromechanical behavior and failure micro-mechanisms involved during its response under various loading conditions. In this study, a uniaxial tensile test is conducted on a low silicon bainitic steel with second phase constituents (martensite and carbides). A comprehensive image processing on SEM micrographs is performed in order to quantify the damage evolution as a function of plastic deformation. A new methodology is examined to address the correlation between crystallographic orientation and damage initiation. In this multiphase steel, it appears that orientation dependence of damage initiation is blurred by the presence of different phases and hence there is not an obvious preferential orientation from where damage has initiated.(OLD) MSE-