Abstract
Commercial Mg alloys, compared to other engineering materials such as steels or aluminum materials have inferior strengths (Y.S. = ~120 MPa), limited ductility and poor formability. Furthermore, due to high costs their use in structural applications for transportation industry is still rather limited. Therefore, there is significant interest in developing microstructure modification routes to produce novel Mg base alloys with an attractive combination of strength and ductility at room temperature as-well as warm temperature formability. In order to promote use of such microstructurally engineered Mg materials, better understanding of the relationship between microstructure, texture etc. with mechanical properties must be developed for a range of different alloys. In this work, microstructure evolution and mechanical response of two thermomechanically processed Mg alloys AZ61L and AZ70-TH were investigated. Initial findings of this work are presented here. The processed materials exhibited a good combination of strength and tensile ductility at room temperature that was further enhanced (Y.S. > 250 MPa, El. % > 10%) by low temperature (180°C) annealing treatment for 1 hr. The ductility and in-plane anisotropy in mechanical property was found to be related to basal texture formation in the sheet plane. In addition to the Hall-Petch strengthening due to near ultrafine grain size, β-particles from as-molded microstructure, complement strengthening by sub-dividing and possibly solutionizing/re-precipitating into nano-sized, well-dispersed, obstacles to dislocation motion and grain growth.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Pollock TM. Weight Loss with Magnesium Alloys. Science. 2010;328:986–7.
Mathaudhu SN, Nyberg EA. Magnesium alloys in US military applications: past, current and future solutions In: Agnew SR, R. NN, A. NE, H. SW, editors. Magnesium Technology 2010 2010. p. 27–32.
Valiev RZ, Korznikov AV, Mulyukov RR. Structure and properties of ultrafine-grained materials produced by severe plastic deformation. Materials Science and Engineering: A. 1993;168:141–8.
Segal VM. Materials processing by simple shear. Materials Science and Engineering: A. 1995; 197: 157–64.
Saito Y, Tsuji N, Utsunomiya H, Sakai T, Hong RG. Ultra-fine grained bulkaluminum produced by accumulative roll-bonding (ARB) process. Scripta Materialia. 1998;39:1221–7.
Ma ZY, Mishra RS, Mahoney MW, Grimes R. High strain rate super plasticity in friction stir processed Al–Mg–Zr alloy. Materials Science and Engineering: A. 2003;351:148–53.
A. Albakri, B. Mansoor, H. Nassar, M. Khraisheh, Thermo-mechanical and metallurgical aspects in friction stir processing of AZ31 Mg alloy—A numerical and experimental investigation, Journal of Materials Processing Technology, 213 (2013) 279–290.
B. Mansoor, A. Ghosh, Microstructure and tensile behavior of a friction stir processed magnesium alloy, Acta Materialia, 60 (2012) 5079–5088.
B. Mansoor, S. Mukherjee, A. Ghosh, Microstructure and porosity in thixomolded Mg alloys and minimizing adverse effects on formability, Materials Science and Engineering: A, 512 (2009) 10–18.
Campbell J. Rheocasting and Thixocasting — a review of progress to-date. Foundry Trade Journal. 1975;138: 291–5.
Decker RF, Carnahan R, Babij E, Mihelich J, Spalding G, Thompson L. Magnesium semi-solid metal forming. Materials Park, OH: ASM International; 1996.
Chen Z, Huang J, Decker R, Lebeau S, Walker L, Cavin O, etal. The Effect of Thermomechanical Processing on the Tensile, Fatigue, and Creep Behavior of Magnesium Alloy AM60. Metallurgical and Materials Transactions A. 2011;42:1386–99.
Park SHC, Sato YS, Kokawa H. Microstructural evolution and its effect on Hall-Petch relationship in friction stir welding of molded Mg alloy AZ91D. Journal of Materials Science. 2003;38:4379–83.
Berman TD, Donlon W, Decker R, Huang J, Pollock TM, Jones JW. Microstructure Evolution in AZ61L During TTMP and Subsequent Annealing Treatments. Magnesium Technology 2011: John Wiley & Sons, Inc.; 2011. p. 599–603.
Ponge D, Gottstein G. Necklace formation during dynamic recrystallization: mechanisms and impact on flow behavior. Acta Materialia. 1998;46:69–80.
Sellars CM. Annealing Process-Recovery, Recrystallization and Grain Growth. Proceedings of 7th Ris Int Symp on Metallurgy and Materials Science Ris National Laboratory, Roskilde, Denmark 1986. p. 69–80.
Lü YZ, Wang QD, Ding WJ, Zeng XQ, Zhu YP. Fracture behavior of AZ91 magnesium alloy. Materials Letters. 2000;44:265–8.
Foley DC, Al-Maharbi M, Hartwig KT, Karaman I, Kecskes LJ, Mathaudhu SN. Grain refinement vs. crystallographic texture: Mechanicalanisotropy in a magnesium alloy. Scripta Materialia. 2011;64:193–6.
Hall EO. The Deformation and Ageing of Mild Steel: III Discussion of Results. Proceedings of the Physical Society Section B. 1951;64:747.
Petch NJ. Cleavage strength of polycrystals. Iron and Steel Institute- Journal. 1953;174 25–8.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2015 TMS (The Minerals, Metals & Materials Society)
About this chapter
Cite this chapter
Mansoor, B., Decker, R.F., LeBeau, S.E. (2015). Strengthening in Thermomechanically Processed Magnesium Alloys. In: Manuel, M.V., Singh, A., Alderman, M., Neelameggham, N.R. (eds) Magnesium Technology 2015. Springer, Cham. https://doi.org/10.1007/978-3-319-48185-2_42
Download citation
DOI: https://doi.org/10.1007/978-3-319-48185-2_42
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-48611-6
Online ISBN: 978-3-319-48185-2
eBook Packages: Chemistry and Materials ScienceChemistry and Material Science (R0)