Microstructure and its Relationship to Mechanical Properties in Equal Channel Angular Rolled Al6061 Alloy Sheets

Document Type : Research Paper

Authors

School of Mechanical Engineering, Semnan University, Semnan, Iran

Abstract

Equal channel angular rolling (ECAR) is a severe  plastic deformation (SPD) technique which has been used to produce metal sheets with ultra-fine grain structure. In the present work, the relationships between the mechanical properties and microstructure of samples during the ECAR process have been investigated. The Rietveld method was applied to analyze the X-ray diffraction pattern and to determine the microstructural characteristics including the crystallite size, microstrain, and dislocation density. It was observed that the average crystallite size and dislocation density increased by increasing the strain during the ECAR process. The results showed that ECAR is a procedure intended to obtain meaningful structural refinement appearing in a crystallite. It can be justified by using Taylor equation that the mechanical properties are related to the dislocation density. The ECAR process strongly increases the yield strength and microhardness due to an increase in the dislocation density over a wide range of strain.

Keywords

References

 [1]  A. Azushima, R. Kopp, A. Korhonen, Severe plastic deformation (SPD) processes for metals, CIRP Ann, 2008; 57: 716–735.
[2]  R. N. Chari, B. M. Dariani, A. F. Arezodar, Numerical and experimental studies on deforamion behavior of 5083 aluminum alloy strips in equal channel angular rolling, Proc Inst Mec Eng, B J Eng Manuf , 2016, https://doi.org.
[3]  M. H. Farshidi, M. Kazeminezhad, The effects of die geometry in tube channel pressing: Severe  plastic deformation, Proc Inst Mech Eng, L J Mater Des Appl, 2016; 230 (1): 263–272.
[4]  M. Mahmoodi, M. Sedighi, D.A. Tanner, Experimental study of process parameters' effect on surface residual stress magnitudes in equal channel angular rolled aluminum alloys, Proc Inst Mech Eng, B J Eng Manuf , 2012; 34: 483–487.
[5]  M. Mahmoodi A. Naderi, Applicability of artificial neural network and nonlinear regression to predict mechanical properties of equal channel angular rolled Al5083 sheets, Lat Am j solids struct, 2014; 228: 1592–1598.
[6]  M. Honarpisheh, E. Haghighat, M. Kotobi, Investigation of residual stress and mechanical propeties of equal channel angular rolled St12 strips, Proc Inst Mech Eng, L J Mater Des Appl, 2016. DOI: 10.1177/1464420716652436.
[7]  J. C. Lee, H. K. Seok, J. Y. Suh, Microstructural evolutions of the Al strip prepared by cold rolling and continuous equal channel angular pressing, Acta Mater, 2002; 50: 4005–4019.
[8]  Y. H. Chung, J. W. Park, K.H. Lee, An Analysis of Accumulated Deformation in the Equal Channel Angular Rolling (ECAR) Process, Metal and Material International, 2006; 12: 289-292.
[9]  Y. H. Chung, J. W. Park, K. H. Lee, Controlling the Thickness Uniformity in Equal Channel Angular Rolling (ECAR), Mater. Sci. Forum, 2007; 539: 2872–2877.
[10]     Y. Q. Cheng, Z. H. Chen, W.J. Xia,  Improvement of drawability at room temperature in AZ31 magnesium alloy sheets processed by equal channel angular rolling, J Mater Eng Perform, 2008; 17: 15–19.
[11]     Y. Q. Cheng, Z. H. Chen, W. J. Xia,  Drawability of AZ31 magnesium alloy sheet produced by equal channel angular rolling at room temperature, Mater, Charact, 2007; 58: 617–622.
[12]     A. Habibi, M. Ketabchi, Enhanced properties of nano-grained pure copper by equal channel angular rolling and post-annealing, Mater, 2012; 34: 483–487.
[13]     M. Mahmoodi, A. Naderi, G. Dini, Correlation between structural parameters and mechanical properties of Al5083 sheets processed by ECAR, J Mater Eng Perform, 2017; 26: 6022–6027.
[14]     M. Kotobi, M. Honarpisheh, Uncertainty analysis of residual stress measured by slitting method in equal-channel angular rolled Al-1060 strips, J Strain Anal Eng Des, 2016; 52 (2): 83-92.
[15]     M. Mahmoodi, S. Lohrasbi, Investigation of residual stresses distribution in equal channel angular rolled aluminum alloy by means of the slitting method, J Strain Anal Eng Des, 2017; 52 (6): 389-396.
[16]     N. Anjabin, A.K. Taheri, Physically based material model for evolution of stress–strain behavior of heat treatable aluminum alloys during solution heat treatment, Mater Des, 2010; 31: 433–437.
[17]     J. Gubicza, N. Q. Chinh, Z. Horita,  Effect of Mg addition on microstructure and mechanical properties of aluminum, Mater Sci Eng, A, 2004; 387-389: 55–59.
[18]     J. Gubicza, N. Q. Chinh, J. L. Labar,  Correlation between microstructure and mechanical properties of severely deformed metals, J Alloys Compd, 2009; 483: 271–274.
[19]     V. M. Segal, Materials processing by simple shear, Materials Science and Engineering A, 1995; 197: 157-164.
[20]     L. Lutterotti, Total pattern fitting for the combined size-strain-stress-texture determination in thin film diffraction, Nucl Instrum Methods Phys Res, Sect B, 2010; 268: 334–340.
[21]     P. Sahu, M. De, S. Kajiwara, Microstructural characterization of stress-induced martensites evoluted at low temperature in deformed powders of Fe-Mn-C alloys by Rietveld method,  J Alloys Compd, 2002; 346: 158–169.
[22]     G. Dini, A. Najafizadeh, S. M. Monir-Vaghefi,  Grain size effect on the martensite formation in a high-manganese TWIP steel by the Rietveld method, J Mater Sci Technol, 2010; 26: 181–186.
[23]     M. R. Rezaei, M. R. Toroghinead, F. Ashrafizadeh, Production of nano-grained structure in 6061 aluminum alloy strip by accumulative roll bonding, Mater Sci Eng, A, 2011; 529: 442–446.
[24]     M. Mahmoodi, The effect of ECAR parameters on residual stresses and mechanical-microstructural properties of Al sheets, PhD Thesis, Iran University of Science and Technology, Iran, 2011.
[25]     M. Janecek, J. Cizek, M. Dopita,  Mechanical properties and microstructure development of ultrafine-grained Cu processed by ECAP, Mater Sci Forum, 2008; 584–586: 440–445.
[26]     J. Tu, T. Zhou, L. Liu, L. Shi,  Effect of rolling speeds on texture modification and mechanical properties of the AZ31 sheet by a combination of equal channel angular rolling and continuous bending at high temperature, Journal of Alloys and Compounds, 2018; 768: 598-607.
[27]     T. Kvackaj, A. Kovacova, R. Kocisko,  Microstructure evolution and mechanical performance of copper processed by equal channel angular rolling, Materials Characterization, 2017; 134: 246–252.
[28]     J. Gubicza, N. Q. Chinh, T. G. Langdon,  Microstructure and strength of metals processed by severe plastic deformation, Ultrafine Grained Materials IV, 2006; 231–236.
[29]     N. Hansen, X. Huang, Microstructure and flow stress of polycrystals and single crystals, Acta Mater, 1998; 46: 1827–1836.
[30]     Z. Y. Zhong, H. G. Brokmeier, W. M. Gan,  Dislocation density evaluation of AA7020-T6 investigated by in-situ synchrotron diffraction under tensile load, Mater Charact, 2015; 108: 124–131.
[31]     Y. Miyajima, S. Okubo, H. Abe,  Dislocation density of pure copper processed by accumulative roll bonding and equal channel angular pressing, Mater Charact, 2015; 104: 101–106.
[32]     W. J. Kim, J. K. Kim, T. Y. Park, S. I. Hong, D. I. Kim, Y. S. Kim, J. D. Lee, Enhancement of Strength and Superplasticity in a 6061 Al Alloy Processed by Equal-Channel-Angular-Pressing, Metallurgical and Materials Transactions A, 2002; 33A: 3155.
Iranian Journal of Materials Forming
Volume 6, Issue 1
April 2019
Pages 16-23

Files

Share

How to cite

Statistics