Abstract
► The advanced high strength steels (AHSS) showed positive strain-rate sensitivity. ► The TRIP steels exhibited higher ductility than the DP steels. ► The deformation texture of the AHSS steels experimented was not significantly influenced by the strain-rate. ► The correlations and prediction from the KHL (Khan–Huang–Liang) constitutive model were close to the observed responses.
Measured responses of advanced high strength steels (AHSS) and their tailor welded blanks (TWBs), over a wide range of strain-rates (10−4 to 103s−1) are presented. The steels investigated include transformation induced plasticity (TRIP), dual phase (DP), and drawing quality (DQ) steels. The TWBs include DQ–DQ and DP–DP laser welds. A tensile split Hopkinson pressure bar (SHPB) was used for the dynamic experiments. AHSS and their TWB’s were found to exhibit positive strain-rate sensitivity. The Khan–Huang–Liang (KHL) constitutive model is shown to correlate and predict the observed responses reasonably well. Micro-texture characterization of DQ steels, DQ–DQ and DP–DP laser welds were performed to investigate the effect of strain-rate on texture evolution of these materials. Electron backscatter diffraction (EBSD) technique was used to analyze the micro-texture evolution and kernel average misorientation (KAM) map. Measurement of micro-hardness profile across the cross section of tensile samples was conducted to understand the effect of initial microstructure on ductility of laser weld samples.