Production of Bulk Ultrafine Grained Steel through Severe Plastic Deformation
In the present research, a combined forward extrusion-equal channel angular pressing (FE-ECAP) was developed and used for production of bulk ultrafine grained steel in the high temperature conditions. In this method, two different deformation steps including forward extrusion and equal channel angular pressing takes place successively in a single die. The deformation process was performed at different deformation start temperatures (800, 930, and 1100 °C). In addition, 3D finite element simulation was used to predict the hot/warm deformation parameters such as strain and temperature variations within the samples during deformation. The results show that the EF-ECAP process is effective in refining the grains from initial size of 32 m to final size of 0.9 m after executing of extrusion and ECAP on as received samples. The main mechanisms of grain refinement were considered to be strain assisted transformation, dynamic strain-induced transformation, and continuous dynamic recrystallization.
Jing Tao Wang, Roberto B. Figueiredo and Terence G. Langdon
M. S. Ghazani and B. Eghbali, "Production of Bulk Ultrafine Grained Steel through Severe Plastic Deformation", Materials Science Forum, Vols. 667-669, pp. 583-588, 2011