Structural characterization of M7C3-type carbide precipitated in the aging treated 100Mn13 steel

The distribution and the microstructure of carbides and pearlite, orientation relationships of pearlitic component phase in 100Mn13 steel by solution treatment at 1050 degrees C and aging treatment at 525 degrees C were investigated by optical microscope and transmission electron microscope. The results show that there is a large number of carbides and pearlite forming within the austenite grain and at the grain boundaries. The carbides in the pearlite of 100Mn13 steel have two kinds of morphologies, namely flaky and short rod. The type of carbides is M7C3. The carbides with different morphologies in the pearlite have different crystallographic orientation relationships with the ferrite. The orientation relationships between the flaky carbides and the ferrite are [GRAPHICS] , [GRAPHICS] , while the orientation relationships between the short-rod carbides and the ferrite are [GRAPHICS] , [GRAPHICS] . The short-rod carbides distribute directionally and orderly on the ferrite, which is similar to the morphology of the interphase precipitate. Therefore, the class-interphase precipitate mechanism is proposed in this study.