Abstract
In this work, the gas forming of AZ31 magnesium alloy 0.75-mm-thick sheets at elevated strain rates (fast gas forming) is investigated through an experimental-numerical approach. First, free inflation tests were carried out to find the conditions, in terms of temperature and forming pressure, able to give the best compromise between the alloy formability and the forming time. The analysis was successively moved to a closed die forming application with a stepped geometry case study in order to analyse the real forming process. Both an axisymmetric model of the free inflation test and a 3D model of the closed die forming process were built to correlate the results from free inflation tests (in terms of optimal strain rate values) to the closed die forming test: Numerical simulations were run to find the pressure value to be applied in gas forming tests. Experimental gas forming trials were finally conducted in order to support the approach and to analyse post-forming characteristics of the formed parts. Results showed that very small fillet radii can be reached on a commercial Mg alloy sheet setting very short forming times (few seconds). The choice of the forming temperature and of the corresponding optimal strain rate strongly affects the grain growth and the cavitation phenomena. Even if the alloy is prone to a strong static and dynamic grain growth at elevated temperatures, a small mean grain size value can be reached in the formed component due to the short forming times.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Neugebauer R, Altan T, Geiger M, Kleiner M, Sterzing A (2006) Sheet metal forming at elevated temperatures. Ann CIRP 55(2):793–816
Lee S, Chen Y-H, Wang J-Y (2002) Isothermal sheet formability of magnesium alloy AZ31 and AZ61. J Mater Process Technol 124:19–24
Boissière R, Blandin JJ, Salvo L (2010) Large deformability of wrought magnesium alloys: is superplasticity needed? Key Eng Mater 433:267–272
Krajewski PE, Schroth JG (2007) Overview of quick plastic forming technology. Mater Sci Forum 551–552:3–12
Sun P-H, Wub H-Y, Tsaib H-H, Huang C-C, Tzoub M-D (2010) Effect of pressurization profile on the deformation characteristics of fine-grained AZ31B Mg alloy sheet during gas blow forming. J Mater Process Technol 210:1673–1679
Zhang D-T, Xiong F, Zhang W-W, Qiu C, Zhang W (2011) Superplasticity of AZ31 magnesium alloy prepared by friction stir processing. Trans Nonferrous Meatals Soc China 21:1911–1916
Chung SW, Higashi K, Kim WJ (2004) Superplastic gas pressure forming of fine-grained AZ61 magnesium alloy sheet. Mater Sci Eng A 372:15–20
Wu H-Y, Sun P-H, Zhu F-J, Liu H-C, Chiu C-H (2012) Tensile properties and shallow pan rapid gas blow forming of commercial fine-grained Mg alloy AZ31B thin sheet. Procedia Eng 36:329–334
El-Morsy A-W, Manabe K-I, Nishimura H (2002) Superplastic forming of AZ31 magnesium alloy sheet into a rectangular pan. Mater Trans 43–10:2443–2448
Kim W-J, Chung SW, Chung CS, Kum D (2001) Superplasticity in thin magnesium alloy sheets and deformation mechanism maps for magnesium alloys at elevated temperatures. Acta Mater 49–16:3337–3345
Lee CJ, Huang JC (2004) Cavitation characteristics in AZ31 Mg alloys during LTSP or HSRSP. Acta Mater 52:3111–3122
Miao Q, Hu L, Wang X, Wang E (2010) Grain growth kinetics of a fine-grained AZ31 magnesium alloy produced by hot rolling. J Alloys Compd 493:87–90
Sorgente D, Scintilla LD, Palumbo G, Tricarico L (2010) Blow forming of AZ31 magnesium alloy at elevated temperatures. Int J Mater Form 3:13–19
Hosokawa H, Chino Y, Shimojima K, Yamada Y, Wen C, Mabuchi M, Iwasaki H (2003) Mechanical properties and blow forming of rolled AZ31 Mg alloy sheet. Mater Trans 44–4:484–489
Verma R, Hector LG, Krajewski PE, Taleff EM (2009) The finite element simulation of high-temperature magnesium AZ31 sheet forming. JOM 61–8:29–37
Carter JT, Krajewski PE, Verma R (2008) The hot blow forming of AZ31 Mg sheet: formability assessment and application development. JOM 60–11:77–81
Sorgente D, Tricarico L (2014) Characterization of a superplastic aluminium alloy ALNOVI-U through free inflation tests and inverse analysis. Int J Mater Form 7:179–187
Abaqus 6.10 online documentation, 2010, © dassault systèmes
Hanna MD (2009) Tribological evaluation of aluminum and magnesium sheet forming at high temperatures. Wear 267:1046–1050
Carpenter AJ, Antoniswamy AR, Carter JT, Hector LG Jr, Taleff EM (2014) A mechanism-dependent material model for the effects of grain growth and anisotropy on plastic deformation of magnesium alloy AZ31 sheet at 450°C. Acta Mater 68:254–266
Sato E, Kuribayashi K, Horiuchi R (1988) Grain growth induced by superplastic deformation in Zn-22% Al alloy. Nippon Kinzoku Gakkai-si 52–11:1043–1050
Yang X-Y, Zhu Y-K, Miura H, Sakai T (2010) Static recrystallization behavior of hot-deformed magnesium alloy AZ31 during isothermal annealing. Trans Nonferrous Metals Soc China 20:1269–1274
Carpenter AJ, Carter JT, Hector Jr, LG, Taleff EM (2013) Gas-pressure bulge forming of Mg AZ31 sheet at 450°C. In: Hort N, Mathaudhu SN, Neelameggham NR, Alderman M (eds), Magnesium technology 2013. TMS (The Minerals, Metals & Materials Society), pp. 139-144
Figueiredo RB, Langdon TG (2012) Influence of rolling direction on flow and cavitation in a superplastic Magnesium alloy processed by equal-channel angular pressing. Mater Sci Eng A 556:211–220
Rabinovich MK, Trifonov VG (1996) Dynamic grain growth during superplastic deformation. Acta Mater 44–5:2073–2078
Fatemi-Varzaneh SM, Zarei-Hanzaki A, Beladi H (2007) Dynamic recrystallization in AZ31 magnesium alloy. Mater Sci Eng A 456:52–57
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Sorgente, D., Palumbo, G., Scintilla, L.D. et al. Gas forming of an AZ31 magnesium alloy at elevated strain rates. Int J Adv Manuf Technol 83, 861–872 (2016). https://doi.org/10.1007/s00170-015-7614-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00170-015-7614-0