Effect of high-pressure torsion on the microstructural evolution and mechanical properties of an Fe-10Ni-7Mn (wt. %) lath martensitic steel

Authors: Kalahroudi, F.J., Koohdar, H., Jafarian, H., Nili-Ahmadabadi, M., Huang, Y. and Langdon, T.G.

Journal: AIP Conference Proceedings

Volume: 1920

eISSN: 1551-7616

ISSN: 0094-243X

DOI: 10.1063/1.5018982

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 microstructure 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 μm in the initial microstructure to around 230 nm after HPT was observed by EBSD. Although based on a rigid body assumption the 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 the 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.

Source: Scopus

Effect of High-pressure Torsion on the Microstructural Evolution and Mechanical Properties of an Fe-10Ni-7Mn (wt. %) Lath Martensitic Steel

Authors: Kalahroudi, F.J., Koohdar, H., Jafarian, H., Nili-Ahmadabadi, M., Huang, Y. and Langdon, T.G.

Journal: 6TH INTERNATIONAL BIENNIAL CONFERENCE ON ULTRAFINE GRAINED AND NANOSTRUCTURED MATERIALS (UFGNSM 2017)

Volume: 1920

ISSN: 0094-243X

DOI: 10.1063/1.5018982

Source: Web of Science (Lite)

Effect of high-pressure torsion on the microstructural evolution and mechanical properties of an Fe-10Ni-7Mn (wt. %) lath martensitic steel

Authors: Kalahroudi, F.J., Koohdar, H., Jafarian, H., Nili-Ahmadabadi, M., Huang, Y. and Langdon, T.G.

Conference: The 6th International Biennial Conference on Ultrafine Grained and Nano-structured Materials

Dates: 12-13 November 2017

Journal: AIP Conference Proceedings

Volume: 1920

Pages: 020050(1)-020050(7)

eISSN: 1551-7616

ISBN: 9780735416123

ISSN: 0094-243X

DOI: 10.1063/1.5018982

Abstract:

© 2017 Author(s). 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 microstructure 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 μm in the initial microstructure to around 230 nm after HPT was observed by EBSD. Although based on a rigid body assumption the 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 the 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.

Source: Manual

Preferred by: Yi Huang