A novel method for preparing bulk ultrafine-grained material: Three dimensional severe plastic deformation

A novel severe plastic deformation method entitled three dimensional severe plastic deformation was proposed for producing bulk ultrafine-grained materials with industry size. Experiment results of 20MnSiV steel indicate that the ferrite was refined to less than 3 μm after single pass 3D-SPD at 650 °C. The yield strength, ultimate tensile strength and elongation are 491.15 MPa, 626.29 MPa and 20.82%, respectively, which are increased by 28.39%, 3.56% and 10.39% as compared with the received sample. The increase in strength and elongation is related to the grain refinement of ferrite and the hindering effect of spheroidized cementite on dislocations.