A micromechanic modeling for transformation induced plasticity in steels

Transformation induced plasticity (TRIP) has been computed by using a micromechanic model, where the Eshelby inclusion theory, the Mori–Tanaka mean field theory and the Weng secant method are combined. This model enables us to understand experimental findings in three types of steels systematically, including (1) the influence of test temperature and strength of stress-induced martensite on elongation in metastable austenitic steels; (2) poor enhancement of elongation by TRIP of retained or precipitated austenite in Ni steels for cryogenic temperature use; and (3) the attractive combination of strength and ductility in Si bearing high strength sheet steels for automobile use that have currently been developed. A question why a small amount of austenite is effective to enhance the ductility in the last steels is clearly demonstrated by the present computations, where the effect of martensite strength for work-hardening is emphasized.