Microstructural characteristics of nano-structured Fe-28.5Ni steel by means of severe plastic deformation

7th International Conference on Nanomaterials by Severe Plastic Deformation

Mousavi Anijdan, S.H.^1 ; Jafarian, H.R.^2 ; Bahrami, A.^3

Department of Materials Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran^1

School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran^2

Department of Materials Engineering, Isfahan University of Technology, Isfahan

84156-83111, Iran^3

关键词: Accumulative roll bonding;    Electron back scatter diffraction;    Micro-structural characteristics;    Nano-structured Fe;    Retained austenite;    Severe plastic deformations;    Ultimate tensile strength;    Uniaxial tensile test;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/194/1/012051/pdf
DOI  :  10.1088/1757-899X/194/1/012051

来源: IOP

【 摘 要 】

Microstructural evolution together with changes in mechanical properties of an high nickel content steel processed by various cycles of accumulative roll bonding (ARB) is explored. It is shown by Electron Backscatter Diffraction (EBSD) analysis that after successive roll bonding processes a stabilized nano-structure is developed containing sufficient amount of ductility under severe plastic deformation. A mean grain size of few hundred nano meter was obtained after 6-cycle of ARB process meaning that the successive ARB cycles made the structure quite refined. The starting material was mainly coming from the transformation of martensite to retained austenite, particularly under high temperature and in high cycle of ARB process. This is an early indication of the stabilization of retained austenite during the ARB process through grain refinement phenomenon. Uniaxial tensile test demonstrated that yield strength significantly improves by only one cycle of ARB process. Successive cycles of ARB process gradually increased the yield and the ultimate tensile strengths at the expense of ductility. The main cause of such a substantial increase in yield strength is discussed. Remarkably high amount of ductility was still observed in a very high amount of deformation that was applied in the 6-cycle ARB process.