Revisit the Efficacy of Transformation‐Induced Plasticity Mechanism and Martensite‐Austenite Composite Fiber Effect on the Increase of Uniform Elongation in Steel

The ductility of a retained austenite (RA)‐bearing steel is conventionally correlated with the gradual transformation of RA into martensite during straining, i.e., transformation‐induced plasticity (TRIP) mechanism. Nevertheless, current experiments and mathematical calculations illustrate that most of the RA transformed into martensite at quite an early stage of tensile straining. The result shows that only 4% of leftover RA exists after the initial tensile loading. It looks like enough RA is not available to operate TRIP to obtain successive ductility in the steel. Inexplicably, current work exhibits the maximum uniform tensile elongation after the major martensite transformation, which contradicts the conventional TRIP‐driven ductility theory. Thus, only 4% RA could be one of the prime factors that operate unfailingly to impart ductility in the steel. This work has created an understanding of the possible factors responsible for the observed ductility in the current steel while TRIP is not operating.