Work Hardening Response of Transformation‐Induced Plasticity and Dual‐Phase Steels to Prestrain

Abstract

AbstractStandard uniaxial tension and repetitive uniaxial tension at different prestrain levels have been conducted for cold‐rolled TRIP780 and DP590 steels. Scan electron microscope (SEM) was performed to observe the microstructures response to prestrain. The instantaneous work hardening rate and transient hardening behavior changing with the prestrain in repetitive tension were discussed in detail. The elastic modulus degradation with prestrain was also identified for the two steels. Results indicated that TRIP780 and DP590 had different work hardening responses to prestrain although they both have preferable work hardenability. When prestrain was small, DP steel had higher work hardening rate than TRIP steel had. While when the prestrain was larger than 2.5%, TRIP780 displayed higher work hardening rate than DP590 did. After each unloading in repetitive tension, the work hardening rate of TRIP780 and DP590 steels fell off and then tended to come back to the original level. The drop of work hardening rate decreased with the prestrain only for TRIP780. It was discerned that the max elastic modulus degradation could reach 18 and 10% for TRIP780 and DP590 steels, respectively.