Tailoring the Mechanical Properties of Copper‐Added Transformation‐Induced Plasticity‐Aided Multiphase Steel by Thermomechanical Processing

Herein, the microstructure and mechanical properties of a low‐alloy Cu‐bearing transformation‐induced plasticity (TRIP) steel and their dependence on the processing history are investigated. The distributions of the retained austenite and bainite are found to be dependent on the initial cold‐rolled microstructure, which can be tailored by the preceding hot‐rolling route (unidirectional/cross rolling) and the subsequent cooling rate (furnace/air cooling). Mechanical properties and TRIP effect strongly depend on the initial microstructure, where the air‐cooled sheet shows remarkable mechanical properties; while the cross‐rolled sheet shows isotropic properties. The addition of copper results in an increase in the amount of the retained austenite, enhancement of strength‐ductility balance, and improvement of the hardening behavior of TRIP‐assisted high‐performance steel. Mechanical properties, transformation‐induced plasticity (TRIP) effect, and the distribution of microstructural features of low‐alloy Cu‐bearing TRIP steel strongly depend on the initial microstructure, which can be tailored by the preceding hot‐rolling route (unidirectional/cross rolling) and the subsequent cooling rate (furnace/air cooling). The addition of copper results in an increase in the amount of the retained austenite and an enhancement of strength‐ductility synergy.