Superplastic Forming Response of a Friction Stir Processed Mg Alloy Sheet – A Numerical Approach

Abstract:

Friction stir process (FSP) is a severe plastic deformation based secondary processing technique that can be utilized to engineer novel microstructures in metallic alloys. It is well known that such techniques are cumbersome and require significant experimental work and material to determine optimum processing conditions. Therefore in this work, we propose a new two step numerical approach, where: (i) CFD simulations coupled with Zener-Holloman relation are used to predict microstructure evolution in stirred, transition and heat affected zones of friction stir processed AZ31 Mg alloy sheets, (ii) Finite element simulations are carried out to evaluate superplastic forming characteristics of different microstructures developed after FSP. Simulation trends including forming pressure profiles, dome height evolution, and thickness distribution of friction stir processed sheets are compared with those of the base material. The proposed combination of numerical approaches to model both processing and forming aspects yields a powerful tool to study and optimize processing and forming technologies with limited experimentation.

• Periodical: Materials Science Forum (Volume 735)
• Pages: 192-197
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.735.192
• Online since: December 2012
• Authors: Mohammad Albakri, Bilal Mansoor, Ahmad Albakri, Marwan Khraisheh
• Keywords: Finite Element Method (FEM), Friction Stir Processing (FSP), Grain Refinement, Layered Microstructure, Superplasticity

References

[1] R. Z. Valiev, A. V. Korznikov, and R. R. Mulyukov, "Structure and properties of ultrafine-grained materials produced by severe plastic deformation," Materials Science and Engineering: A, vol. 168, no. 2, p.141–148, Aug. 1993.

DOI: 10.1016/0921-5093(93)90717-s

[2] Z. Y. Ma, "FSP Technology: A Review," Metallurgical and Materials Transactions A, vol. 39, no. 3, p.642–658, 2008.

[3] M. W. Mahoney, A. J. Barnes, W. H. Bingel, and C. B. Fuller, "Superplastic Forming of 7475 Al Sheet after Friction Stir Processing (FSP)," Materials Science Forum, vol. 447–448, p.505–512, 2004.

DOI: 10.4028/www.scientific.net/msf.447-448.505

[4] M. A. Nazzal and M. K. Khraisheh, "Impact of Selective Grain Refinement on Superplastic Deformation: Finite Element Analysis," Journal of Materials Engineering and Performance, vol. 17, no. 2, p.163–167, Dec. 2007.

DOI: 10.1007/s11665-007-9180-6

[5] B. Mansoor, M. Albakri, A. Albakri, and M.K. Khraisheh, "Microstructure and Superplasticity in a Friction Stir Processed Magnesium Alloy," 9th Int. Conference on Mg Alloys and their Applications, Vancouver, Canada, 2012.

DOI: 10.4028/www.scientific.net/msf.735.192

[6] A. N. Albakri, B. Mansoor, H. Nassar, and M. K. Khraisheh, "Simulation of Friction Stir Processing with Internally Cooled Tool," Advanced Materials Research, vol. 445, p.560–565, Jan. 2012.

DOI: 10.4028/www.scientific.net/amr.445.560

[7] C. M. Sellars and W. J. M. Tegart, "Hot Workability," Int. Metallurgical Reviews, vol. 17, no. 1, p.1–24, Jan. 1972.

DOI: 10.1179/imtlr.1972.17.1.1

[8] K. E. Tello, A. P. Gerlich, and P. F. Mendez, "Constants for hot deformation constitutive models for recent experimental data," Science and Technology of Welding & Joining, vol. 15, no. 3, p.260–266, Apr. 2010.

DOI: 10.1179/136217110x12665778348380

[9] C. I. Chang, C. J. Lee, and J. C. Huang, "Relationship between grain size and Zener–Holloman parameter during friction stir processing in AZ31 Mg alloys," Scripta Materialia, vol. 51, no. 6, p.509–514, Sep. 2004.

DOI: 10.1016/j.scriptamat.2004.05.043

[10] C. H. Caceres and D. S. Wilkinson, "Large strain behavior of a superplastic copper alloy–II. Cavitation and fracture," Acta Metallurgica, vol. 32, no. 3, p.423–434, 1984.

DOI: 10.1016/0001-6160(84)90116-0

[11] American Welding Society, AWS Welding handbook, 7th ed., vol. 3. 2007.

[12] F. K. Abu-Farha and M. K. Khraisheh, "Analysis of superplastic deformation of AZ31 magnesium alloy," Advanced Engineering Materials, vol. 9, no. 9, p.777–783, 2007.

DOI: 10.1002/adem.200700155