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Dual phase steels are being extensively considered as a structural material for automobiles because of the favourable combination of strength and formability. Crashworthiness of these new steels is an area of great importance. High strain rate testing is one approach to measure the ability of materials to absorb energy in a crash situation. The objective of this paper is to examine the effect of the deformation rate on the mechanical properties of dual-phase and multi-phase steels. Shear-punch experiments are conducted both at quasi-static and dynamic rates for this purpose. The ease of preparation of shear punch specimens compared to the tension specimen makes this approach attractive in evaluating key mechanical properties, such as ultimate tensile strength (UTS) and ductility limits, of automotive materials mostly in sheet forms.

Understanding the role of the slip systems and their evolution with temperature is critical to the correct simulation of the mechanical behavior of magnesium alloys. In this paper, relations are proposed for evolution of the CRSS values of different slip systems and strain-rate sensitivity factor, stating them as functions of temperature and strain-rate. These relations are used in conjunction with the Crystal Plasticity Finite Element (CPFE) model for prediction of stress-strain curves and r-values at elevated temperatures (75°C to 250°C). The new relations can predict the decrease in stress level, the anisotropy of the material, and the decrease in the difference between the r-values in the RD and the TD with the increase in temperature. The results confirm the trends predicted with Taylor-type and VPSC models. In particular, they confirm the high activity of the slip systems at higher temperatures.