On the capability of severe plastic deformation of twining induced plasticity (TWIP) steel

There are few reports showing that severe plastic deformation of relatively high strength materials such as steels is difficult due to the segmented flow. In the present paper, it is shown that twining induced plasticity (TWIP) steel can be processed successfully by simple shear extrusion without segmentation. Two simple shear extrusion dies with the maximum distortion angle of 30° and 45° are considered. For comparison, TWIP steel is also processed by equal channel angular pressing at two strain rates. Results show that equal channel angular pressing leads to the segmented flow due to flow localization while simple shear extrusion has the capability of processing TWIP steel without cracking. The microstructure after one pass of simple shear extrusion consists of many deformation twins due to imposing large plastic strains into the material.