Formation of Micro Shear Bands During Severe Plastic Deformation of BCC Alloys

Document Type : Original Research Paper

Authors

1 Metallurgical Engineering and Materials Science Department, Ferdowsi University of Mashhad, Mashhad, Iran.

2 Mechanical Engineering Department, Doshisha University, Kyotanabe, Kyoto, Japan.

Abstract

In this work, tendencies of pure Niobium, Fe-20Cr stainless steel, and Ti-36Nb-2Ta-3Zr to formation of micro shear bands inside their microstructures during severe plastic deformation are compared with their mechanical properties. For this purpose, strain hardening behavior and strain rate sensitivity of flow stress of these alloys were measured using tension tests and nano-indentation tests, respectively. Microstructures of the alloys were studied using electron backscattering diffraction method before and after imposition of severe plastic deformation. Results show that increase of the strain hardening exponent and/or strain rate sensitivity of flow stress causes decrease of tendency to formation of micro shear bands during deformation. Moreover, formation of micro shear bands can be approximately predicted using a parameter
previously proposed for prediction of formation of macro shear bands.

Keywords


[1] Y. Xu, J. Zhang, Y. Bai, M.A. Meyers, Shear localization in dynamic deformation: microstructural evolution, Met. Mater. Transact. A, 39 (2008) 811-843.
[2] I. Sabirov, Y. Estrin, M.R. Barnett, I. Timokhina, P.D. Hodgson, Tensile deformation of an ultrafinegrained aluminium alloy: Micro shear banding and grain boundary sliding, Acta Mater., 56(10) (2008) 2223-2230.
[3] H. Miyamoto, T. Xiao, T. Uenoya, M. Hatano, Effect of simple shear deformation prior to cold rolling on texture and ridging of 16% Cr ferritic stainless steel sheets, ISIJ Internat., 50(11) (2010) 1653-1659.
[4] X.H. An, Q.Y. Lin, S.D. Wu, Z.F. Zhang, Microstructural evolution and shear fracture of Cu-16 at.% Al alloy induced by equal channel angular pressing, Mater. Sci. Eng. A, 527(16-17) (2010) 4510-4514.
[5] I. Sabirov, M.Y. Murashkin, R.Z. Valiev, Nanostructured aluminium alloys produced by severe plastic deformation: New horizons in development, Mater. Sci. Eng. A, 560 (2013) 1-24.
[6] H. Miyamoto, T. Ikeda, T. Uenoya, A. Vinogradov, S. Hashimoto, Reversible nature of shear bands in copper single crystals subjected to iterative shear of ECAP in forward and reverse directions, Mater. Sci. Eng. A, 528(6) (2011) 2602-
2609.
[7] F. Kang, J.T. Wang, Y. Peng, Deformation and fracture during equal channel angular pressing of AZ31 magnesium alloy, Mater. Sci. Eng. A, 487(1-2) (2008) 68-73.
[8] I.L. Dillamore, J.G. Roberts, A.C. Bush, Occurrence of shear bands in heavily rolled cubic metals, Metal. Sci., 13(2) (1979) 73-77.
[9] S.D. Antolovich, R.W. Armstrong, Plastic Strain Localization in Metals: Origins and Consequences, Prog. Mater. Sci., 59 (2014) 1-160.
[10] R.B. Figueiredo, P.R. Cetlin, T.G. Langdon, Stable and unstable flow in materials processed by equal-channel angular pressing with an emphasis on magnesium alloys, Metall. Mater. Transact. A, 41(4) (2010) 778-786.
[11] T.W. Wright, Shear band susceptibility: Work hardening materials, Int. J. Plast., 8(5) (1992) 583-602.
[12] V.M. Kiener, K. Durst, Advanced nanoindentation testing for studying strain-rate sensitivity and activation volume, JOM, 69(11) (2017) 2246-2255.
[13] C. Brozek, F. Sun, P. Vermaut, Y.Millet, A. Lenain , D. Embury, P.J. Jacques, F. Prima, A β-titanium alloy with extra high strain-hardening rate: Design and mechanical properties, Scri. Mater., 114 (2016) 60-64.
[14] S.L. Semiatin, J.J. Jonas, Formability and workability of metals, ASM, Ohio, (1984) 43-120.
[15] S.L. Semiatin, V.M. Segal, R.L. Goetz, Workability of a gamma titanium aluminide alloy during channel angular extrusion, Scri. Metall. Mater., 33(4) (1995) 535-540.
[16] F. Delaire, J.L. Raphanel and C. Rey, Plastic heterogeneities of a copper multicrystal deformed in uniaxial tension: experimental study and finite element simulations, Acta Mater., 48 (2000) 1075-1087.