| Effect of High Pressure Torsion on the Microstructural Evolution and Mechanical Properties of an Fe-10Ni-7Mn (wt. %) Lath Martensitic Steel |
| Paper ID : 1650-UFGNSM-FULL |
| Authors: |
|
Faezeh Javadzadeh Kalahrodi * School of Metallurgy and Materials Engineering, University of Tehran, P.O. Box 14395-731, Tehran, Iran |
| Abstract: |
| The high pressure torsion (HPT) process is a severe plastic deformation (SPD) technique which imposes exceptionally high strains to produce extremely small grain sizes in bulk materials. In this paper, the HPT process was carried out on an Fe-10Ni-7Mn (wt.%) martensitic steel up to 20 revolutions at a rotation speed of 1 rpm under a pressure of 6.0 GPa at room temperature. The effects of the HPT process on the microstructural evolution and mechanical properties of the alloy were investigated by X-ray diffraction (XRD) analysis, electron backscatter diffraction (EBSD), micro-hardness measurement and conventional tensile testing. The XRD analysis revealed no changes in the detected phases after deformation. A significant refinement in grain size from 200 m in the initial microstructure to around 250 nm after HPT was observed by EBSD. Although imposed strain is linearly proportional to the distance from the center in HPT-processed disks, after 20 revolutions a uniform micro-hardness increment up to ~650 Hv was achieved. Moreover, the tensile strength of the alloy increased from 800 MPa in the solution annealed condition to about 2300 MPa after HPT process with a total tensile strain of 4%. Experimental results indicated that the HPT process leads to improvement of the tensile strength with a reasonable ductility due to the significant refinement of the microstructure. |
| Keywords: |
| Fe–10Ni–7Mn (wt.%) alloy, High pressure torsion (HPT), Reverse transformation, Microstructure, Mechanical properties |
| Status : Paper Accepted (Poster Presentation) |
