Research On Transformation Mechanism Of Bainite And Martensite In Steel Of 35crmo Ect.

In this paper observed bainite,martensite,surface relief by austempering,direct quenching and vacuum heat treatment with industrial steel 35CrMo ect. Investigated by transmission electron microscopy (JEM-2100F) ,environmental scanning electron microscope (Quanta-400) ,scanning tunneling microscopy(Nanofrist-1000) and optical microscopy (LeiCa) and so on.The results show that bainite ferrite nucleating in grain boundary,then grow up along boundary or into austenite grain. Bainite ferrite embryo nucleus formed by transition of thermal activation of Fe and replacement atoms in carbon-depleted region.The carbide in bainite formed by transition of thermal activation that interface controlled.The C atom long range diffusion along phase interface.The Fe and replacement atoms moving by transition of thermal activation.martensite sub-structure is very complex. sub-structure of low carbon lath martensite is high density dislocation and stacking fault. high carbon martensite sub-structure is high density dislocation and a large amount twin crystal. Fe-15Ni-0.6C martensitic plate's surface relief is the type of tent(Λ).Its'height is 43-96nm. surface relief of martensitic is formed by volume expansion that phase transited,is not the process of shear. The martensite`shear theory lack of experimental basis.Finally, carry on the discussion about martensite phase change mechanism,then put forward new mechanism. That is martensite'nucleating and growing is by all atoms moving on group collaborative transition of thermal of no diffusion activation.