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The effects of silicon and manganesecontents on volume fraction and stability of retained austenite particles in 0.2C-(1.0-2.5)Si-(1 .0-2.5)Mn (masso/o) TRIP-aided dual-phase steels were investigated. In addition, the relationships betweenabove retained austenite parameters and ductility at room and moderate temperatu res wered iscussed th rough stud ies on stra in-i nducedtransformation behavior of reta ined austen ite.As increasing the silicon and manganese contents except for 2.5 masso/o manganese steel, the initial volume fraction of retained austenite increased with accompaniedby reducing carbon concentration in retained austenite, It was found that the ductilities of these steels becamemaximum at a given temperature between 23 and 1 75'C, i,e,, a peak temperature, The peak temperature was concluded to agree well with the temperature at which the sttain-induced transformation of retained austenite was suppressed moderately for each steel. Moreover, the peak temperature Tp ('C) was related to estimated martensite-start temperature Ms ('C) of the retained austenite as Tp=3.04Ms+187.Strength-ductility balance, i.e., the product of tensile strength and total elongation, at the peak temperature linearly increased with an increase in (2) And, the relationship between these retained austenite parameters and the ductility (the total elongation and the peak temperature) was investigated through the studies of strain induced transformation behaviors.Eq. (1)