Rate-Dependent Hardening Behavior and TRIP Effect in Quenching and Partitioning Steels for Application in Crash Energy-Absorbing Structures

Belonging to the 3rd generation of Advanced High Strength Steels (AHSS), Quenching and Partitioning (Q&P)-steels exhibit an excellent combination of high strength and good ductility while having a similar alloying concept as the already existing 1st and 2nd generation AHSS, such as DP- and TRIP-steels. To widen the understanding of mechanical response to high-speed loading, a broad range of strain rates from 0.0001/s up to 1000/s was studied for two grades of Q&P-steels, namely QP980 and QP1180. Special attention is given to the hardening behavior, which is influenced by a rate-dependent TRIP effect. The strain rate effect on the microstructure evolution is also investigated to enable the connection of the rate-dependent TRIP effect with the respective mechanical response.