TEM observation of the fine structure of bainite

Fine structure of bainite, morphology and distribution of carbide in steels and morphology of bainite in Cu-Zn-Al alloy have been investigated with TEM. Interfacial structure ledges and interfacial lattice images of Cu-Zn-Al alloy have also been observed with HREM. Addition of minor alloying elements can fine the structure of bainitic ferrite markedly. The bainitic ferrite is composed of subunits or subchunks. The carbides with different morphologies are distributed between the laths, inside the plates and at the boundaries of subunits. There are abundant fine structures in bainitic ferrite. In the primary bainite of Cu-Zn-Al alloy there are interfacial structure ledges, whose heights are within 3-40 nm, corresponding to 15-200 atomic layers. The phase reaction mechanism of bainite is discussed in this article.