Research Papers

Microstructure Stability of a Fine-Grained AZ31 Magnesium Alloy Processed by Constrained Groove Pressing During Isothermal Annealing

[+] Author and Article Information
Kai Soon Fong

Forming Technology Group,
Singapore Institute of
Manufacturing Technology,
71 Nanyang Drive,
Singapore 638075, Singapore
e-mail: ksfong@SIMTech.a-star.edu.sg

Ming Jen Tan

School of Mechanical and
Aerospace Engineering,
Nanyang Technological University,
50 Nanyang Avenue,
Singapore 639798, Singapore
e-mail: mmjtan@ntu.edu.sg

Fern Lan Ng

Measurements and Characterization Unit,
Singapore Institute of
Manufacturing Technology,
71 Nanyang Drive,
Singapore 638075, Singapore
e-mail: flng@SIMTech.a-star.edu.sg

Atsushi Danno

Forming Technology Group,
Singapore Institute of
Manufacturing Technology,
71 Nanyang Drive,
Singapore 638075, Singapore
e-mail: danno@SIMTech.a-star.edu.sg

Beng Wah Chua

Forming Technology Group,
Singapore Institute of
Manufacturing Technology,
71 Nanyang Drive,
Singapore 638075, Singapore
e-mail: bwchua@simtech.a-star.edu.sg

Manuscript received August 17, 2016; final manuscript received April 6, 2017; published online May 8, 2017. Assoc. Editor: Yannis Korkolis.

J. Manuf. Sci. Eng 139(8), 081007 (May 08, 2017) (9 pages) Paper No: MANU-16-1434; doi: 10.1115/1.4036529 History: Received August 17, 2016; Revised April 06, 2017

In this study, an AZ31 magnesium alloy plate was processed by constrained groove pressing (CGP) under three deformation cycles at temperatures from 503 to 448 K. The process resulted in a homogeneous fine grain microstructure with an average grain size of 1.8 μm. The as-processed microstructure contained a high fraction of low-angle grain boundaries (LAGB) of subgrains and dislocation boundaries that remained in the structure due to incomplete dynamic recovery and recrystallization. The material's yield strength was found to have increased from 175 to 242 MPa and with a significant weakening of its initial basal texture. The microstructure stability of the CGP-processed material was further investigated by isothermal annealing at temperature from 473 to 623 K and for different time. Abnormal grain growth was observed at 623 K, and this was associated with an increased in nonbasal grains at the expense of basal grains. The effect of annealing temperature and time on the grain growth kinetics was interpreted by using the grain growth equation,  Dn+D0n=kt, and Arrhenius equation, k=k0exp((Q/RT)). The activation energy (Q) was estimated to be 27.8 kJ/mol which was significantly lower than the activation energy for lattice self-diffusion (QL = 135 kJ/mol) and grain boundary diffusion (Qgb = 92 kJ/mol) in pure magnesium. The result shows that grain growth is rapid but average grain size still remained smaller than the as-received material, especially at the shorter annealing time.

Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.


Monteiro, W. A. , Buso, S. J. , and Da, L. V. , 2012, “ Application of Magnesium Alloys in Transport,” New Features on Magnesium Alloys, InTech, Rijeka, Croatia.
James, M. , Kihiu, J. M. , Rading, G. O. , and Kimotho, J. K. , 2013, “ Use of Magnesium Alloys in Optimizing the Weight of Automobile: Current Trends and Opportunities,” Jomo Kenyatta University of Agriculture and Technology, Juja, Kenya, accessed Apr. 28, 2017, http://journals.jkuat.ac.ke/index.php/sri/article/view/49/52
Barnett, M. R. , 2007, “ Twinning and the Ductility of Magnesium Alloys: Part I: ‘Tension’ Twins,” Mater. Sci. Eng., A, 464(1–2), pp. 1–7. [CrossRef]
Hirsch, J. , and Al-Samman, T. , 2013, “ Superior Light Metals by Texture Engineering: Optimized Aluminum and Magnesium Alloys for Automotive Applications,” Acta Mater., 61(3), pp. 818–843. [CrossRef]
Zarandi, F. , and Yue, S. , 2011, “ Magnesium Sheet; Challenges and Opportunities,” Magnesium Alloys—Design, Processing and Properties, F. Czerwinski , ed., InTech, Rijeka, Croatia.
Suh, J. , Victoria-Hernandez, J. , Letzig, D. , Golle, R. , Yi, S. , Bohlen, J. , and Volk, W. , 2014, “ Improvement of Ductility at Room Temperature of Mg-3Al-1Zn Alloy Sheets Processed by Equal Channel Angular Pressing,” Procedia Eng., 81, pp. 1517–1522. [CrossRef]
Zhan, M.-Y. , Zhang, W.-W. , and Zhang, D.-T. , 2011, “ Production of Mg-Al-Zn Magnesium Alloy Sheets With Ultrafine-Grain Microstructure by Accumulative Roll-Bonding,” Trans. Nonferrous Met. Soc. China, 21(5), pp. 991–997. [CrossRef]
Yang, Q. , and Ghosh, A. K. , 2006, “ Production of Ultrafine-Grain Microstructure in Mg Alloy by Alternate Biaxial Reverse Corrugation,” Acta Mater., 54(19), pp. 5147–5158. [CrossRef]
Chang, C. I. , Lee, C. J. , and Huang, J. C. , 2004, “ Relationship Between Grain Size and Zener–Holloman Parameter During Friction Stir Processing in AZ31 Mg Alloys,” Scr. Mater., 51(6), pp. 509–514. [CrossRef]
Young, J. P. , Askari, H. , Hovanski, Y. , Heiden, M. J. , and Field, D. P. , 2015, “ Thermal Microstructural Stability of AZ31 Magnesium After Severe Plastic Deformation,” Mater. Charact., 101, pp. 9–19. [CrossRef]
Ma, J. , Yang, X. , Huo, Q. , Sun, H. , Qin, J. , and Wang, J. , 2013, “ Mechanical Properties and Grain Growth Kinetics in Magnesium Alloy After Accumulative Compression Bonding,” Mater. Des., 47, pp. 505–509. [CrossRef]
Fong, K. S. , Tan, M. J. , Chua, B. W. , and Atsushi, D. , 2015, “ Enabling Wider Use of Magnesium Alloys for Lightweight Applications by Improving the Formability by Groove Pressing,” Procedia CIRP, 26, pp. 449–454. [CrossRef]
Fong, K. S. , Atsushi, D. , Tan, M. J. , and Chua, B. W. , 2015, “ Effect of Deformation and Temperature Paths in Severe Plastic Deformation Using Groove Pressing on Microstructure, Texture, and Mechanical Properties of AZ31-O,” ASME J. Manuf. Sci. Eng., 137(5), p. 051004. [CrossRef]
Kim, H. K. , and Kim, W. J. , 2004, “ Microstructural Instability and Strength of an AZ31 Mg Alloy After Severe Plastic Deformation,” Mater. Sci. Eng., A, 385(1–2), pp. 300–308. [CrossRef]
Stráská, J. , Janeček, M. , Čížek, J. , Stráský, J. , and Hadzima, B. , 2014, “ Microstructure Stability of Ultra-Fine Grained Magnesium Alloy AZ31 Processed by Extrusion and Equal-Channel Angular Pressing (EX–ECAP),” Mater. Charact., 94, pp. 69–79. [CrossRef]
Wang, X. , Hu, L. , Liu, K. , and Zhang, Y. , 2012, “ Grain Growth Kinetics of Bulk AZ31 Magnesium Alloy by Hot Pressing,” J. Alloys Compd., 527, pp. 193–196. [CrossRef]
Ma, Q. , Li, B. , Marin, E. B. , and Horstemeyer, S. J. , 2011, “ Twinning-Induced Dynamic Recrystallization in a Magnesium Alloy Extruded at 450 °C,” Scr. Mater., 65(9), pp. 823–826. [CrossRef]
Kuhlmann-Wilsdorf, D. , 1991, “ Geometrically Necessary, Incidental and Subgrain Boundaries,” Scr. Metall. Mater., 25(7), pp. 1557–1562. [CrossRef]
Galiyev, A. , Kaibyshev, R. , and Sakai, T. , 2003, “ Continuous Dynamic Recrystalllization in Magnesium Alloy,” Mater. Sci. Forum, 419–422, pp. 509–514. [CrossRef]
Tan, J. C. , and Tan, M. J. , 2003, “ Dynamic Continuous Recrystallization Characteristics in Two Stage Deformation of Mg-3Al-1Zn Alloy Sheet,” Mater. Sci. Eng., A, 339(1), pp. 124–132. [CrossRef]
Watanabe, H. , Tsutsui, H. , Mukai, T. , Ishikawa, K. , Okanda, Y. , Kohzu, M. , and Higashi, K. , 2001, “ Grain Size Control of Commercial Wrought Mg-Al-Zn Alloys Utilizing Dynamic Recrystallization,” Mater. Trans., 42(7), pp. 1200–1205. [CrossRef]
Xu, S. W. , Kamado, S. , and Honma, T. , 2010, “ Recrystallization Mechanism and the Relationship Between Grain Size and Zener–Hollomon Parameter of Mg–Al–Zn–Ca Alloys During Hot Compression,” Scr. Mater., 63(3), pp. 293–296. [CrossRef]
Shin, D. H. , Park, J.-J. , Kim, Y.-S. , and Park, K.-T. , 2002, “ Constrained Groove Pressing and Its Application to Grain Refinement of Aluminum,” Mater. Sci. Eng., A, 328, pp. 98–103. [CrossRef]
Zhan, M.-Y. , Li, Y.-Y. , and Chen, W.-P. , 2008, “ Improving Mechanical Properties of Mg-Al-Zn Alloy Sheets Through Accumulative Roll-Bonding,” Trans. Nonferrous Met. Soc. China, 18(2), pp. 309–314. [CrossRef]
Bruno, J. C. , and Rios, P. R. , 1995, “ The Grain Size Distribution and the Detection of Abnormal Grain Growth of Austenite in an Eutectoid Steel Containing Biobium,” Scr. Metall. Mater., 32(4), pp. 601–606. [CrossRef]
Humphreys, F. J. , and Hatherly, M. , 1995, Recrystallization and Related Annealing Phenomena (Pergamon Materials Series), Pergamon, Hertfordshire, UK.
Mishra, S. K. , Tiwari, S. M. , Carter, J. T. , and Tewari, A. , 2014, “ Texture Evolution During Annealing of AZ31 Mg Alloy Rolled Sheet and Its Effect on Ductility,” Mater. Sci. Eng., A, 599, pp. 1–8. [CrossRef]
Burke, J. E. , and Turnbull, D. , 1953, “ Recrystallization and Grain Growth,” Prog. Met. Phys., 3(1), pp. 220–244.
Eichelkraut, H. , Abbruzzese, G. , and Lucke, K. , 1988, “ A Theory of Texture Controlled Grain Growth—II. Numerical and Analytical Treatment of Grain Growth in the Presence of Two Texture Components,” Acta Metall., 36(1), pp. 55–68. [CrossRef]
Bhattacharyya, J. J. , Agnew, S. R. , and Muralidharan, G. , 2015, “ Texture Enhancement During Grain Growth of Magnesium Alloy AZ31B,” Acta Mater., 86, pp. 80–94. [CrossRef]
Shewmon, P. G. , 1956, “ Self-Diffusion in Magnesium Single Crystals,” JOM, 206(1), pp. 918–922. [CrossRef]
Frost, H. J. , and Ashby, M. F. , 1982, Deformation-Mechanism Maps: The Plasticity and Creep of Metals and Ceramics, Pergamon, Oxford, UK.
Wang, J. , Iwahashi, Y. , Horita, Z. , Furukawa, M. , Nemoto, M. , Valiev, R. Z. , and Langdon, T. G. , 1996, “ An Investigation of Microstructural Stability in an Al-Mg Alloy With Submicrometer Grain Size,” Acta Mater., 44(7), pp. 2973–2982. [CrossRef]


Grahic Jump Location
Fig. 1

(a) Schematic of the CGP cycle (black arrow indicates the rolling direction of the plate) and (b) dimensions of the grooved dies

Grahic Jump Location
Fig. 2

Microstructure of the (a) as-received and CGP-processed AZ31 alloy after (b) first, (c) second, and (d) third cycles

Grahic Jump Location
Fig. 3

EBSD measurement of the microstructure after CGP: (a) orientation map, (b) misorientation distribution profile, (c) grain boundary map (LAGB in the range of 2–15 deg were delineated by thin lines, and HAGB above 15 deg were delineated by thick lines), and (d) grain orientation spread map

Grahic Jump Location
Fig. 4

Pole figures of the (a) as-received and (b) CGP-processed alloy

Grahic Jump Location
Fig. 5

The true stress–strain curves of the as-received and CGP-processed AZ31 alloy after first to third cycle along the (a) RD and (b) TD directions

Grahic Jump Location
Fig. 6

Microstructures at different annealing temperatures and time

Grahic Jump Location
Fig. 7

Superposition of normalized grain size distributions at (a) 473 K, (b) 523 K, (c) 573 K, and (d) 623 K for different annealing time

Grahic Jump Location
Fig. 8

Relationship between texture and annealing time at different temperatures: (a) 473 K, (b) 523 K, (c) 573 K, and (d) 623 K

Grahic Jump Location
Fig. 9

Plot of (a) hardness against time and (b) average grain size against time at different temperatures

Grahic Jump Location
Fig. 10

Plot of ln(dD/dt) against ln(D) (a), D5.4 − D05.4 against annealing time (b), and lnK against 1000/T (c)




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In