On the work-hardening mechanism of TWIP steels strengthened by nanometre-sized vanadium carbides

Experiments reveal that while dispersed nanometer-sized vanadium carbides can greatly increase the yield strength of twinning induced plasticity (TWIP) steels, they may cause some reduction of the overall work-hardening rate. A modified physically based model is adopted in the present work to capture the effect of nanometer-sized vanadium carbides on the work-hardening rate of a laboratory FeMnC austenitic TWIP grade. It is found that the introduction of the dispersed nanometer-sized carbides leads to a faster dislocation accumulation rate but reduces the rate of twin formation with strain during plastic deformation. Compared to a reference alloy without precipitates the work-hardening rate is higher at small strains but decreases faster than the reference thus presenting a lower work-hardening rate at high strains.