Deformation Behavior of Low Carbon TRIP Sheet Steels at High Strain Rates

Two high strength transformation-induced plasticity (TRIP) sheet steels with 0.10wt% and 0.14wt% carbon were produced with retained austenite volume fractions varying from less than 3 % up to 16 %. These TRIP steels were tensile tested at strain rates ranging from 10 -3 to 2.5×10 2 s -1 to determine the effects of strain rate and retained austenite volume fraction on tensile properties. Increasing the retained austenite volume fraction increases UTS, total elongation, uniform strain and total absorbed energy, but decreases yield strength and absorbed energy below 10% engineering strain. Increasing strain rate increases yield strength and UTS, and creates a better-defined yield point, but has little effect on strain hardening behavior for TRIP steels with 11 % or less retained austenite. The TRIP steel with 16% retained austenite shows increasing strain hardening rate with strain rate at low strains.