Effect of time interval on microstructure evolution of medium carbon steel during warm deformation

The thermal mechanical simulator system (Gleeble-3500) was used to carry out the double passes compression tests. The microstructure evolution of medium carbon steel with different time intervals during warm deformation was investigated by scanning electron microscopy, transmission electron microscopy and electron back-scattered diffraction. The results show that the effects of time interval on microstructure evolution are very important. The low-angle boundaries transform into high-angle boundaries (HABs) during interval. The fraction of HABs and homogeneity of particle carbides increase with increasing time interval. In addition, the homogeneity of carbides also increases with the strain. However, the effects of time interval on the microstructure evolution are negligible when it exceeds 100 s.