Synopsis : The effects of silicon and manganese contents on volume fraction and stability of retained austenite in 0.2C(1.0-2.5) Si(1.0-2.5) Mn ( mass% ) TRIP-aided dual-phase steels were investigated. And, relationship between the above retained austenite parameters and ductility at room and moderate temperatures was discussed through studies on strain-induced transformation behavior of retained austenite. Increasing silicon and manganese contents except for 2.5 mass% manganese steel, initial volume fraction of retained austenite increased with reducing carbon concentration in retained austenite. It was found that ductilities of these steels became maximum at a given temperature between 23•Ž and 175•Ž, i.e., peak temperature. The peak temperature of ductility was concluded to differ among the steels and agree well with the temperature at which strain-induced martensite transformation of retained austenite was suppressed moderately. Moreover, the peak temperature Tp (•Ž) was related to estimated martensite-start temperature Ms(•Ž) of the retained austenite as Tp = 3.04•EM+ 187. Strength-ductility balance at the
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