Effect of Temperature on the Shock-Induced α to ε Phase Transition of Low Carbon Steel

It is well-known that pure iron exhibits a polymorphic α to ε phase transition at pressures around 13 GPa. However, this can vary due to a material's alloying elements and temperature. Here, the state space of a low carbon steel is studied near and above the phase transition at both room temperature and preheated to 200°C. Experiments were conducted using a single-stage light gas gun where the free-surface particle velocity was monitored with photonic doppler velocimetry. The results were compared to a temperature-pressure phase diagram generated in Thermo-Calc. These results can be used to develop a well-informed material model to predict the dynamic behavior of steel for critical applications involving extreme pressures and rates of deformation.