Determination of FLD for Ti-6Al-4V Titanium Alloy Sheet

Abstract:

Ti-6Al-4V is the most widely applied titanium alloy in technology and medicine due its good mechanical properties combined with low density and good corrosion resistance. However, poor technological and tribological properties make it very difficult to process, including the problems with sheet-metal forming. The best way to evaluate sheet drawability is to use Forming Limit Diagram (FLD), which represents a line at which failure occurs. FLD allows for determination of critical forming areas.The FLDs can be determined both theoretically and experimentally. Recently, special optical strain measurement systems have been used to determine FLDs.In this study, material deformation was measured with the Aramis system that allows for real-time observation of displacements of the stochastic points applied to the surface using a colour spray. The FLD was determined for Ti-6Al-4V titanium alloy sheet with thickness of 0.8 mm. In order to obtain a complete FLD, a set of 6 samples with different geometries underwent plastic deformation in stretch forming i.e. in the Erichsen cupping test until the appearance of fracture.The real-time results obtained from the ARAMIS software for multiple measurement positions from the test specimen surface were compared with numerical simulations of the cupping tests. The numerical simulations were performed using the PamStamp 2G v2012 software dedicated for analysis of sheet-metal forming processes. PamStamp 2G is based on the Finite Element method (FEM). The major and minor strains were analysed. The effect of friction conditions on strain distribution was also taken into consideration

• Periodical: Key Engineering Materials (Volume 687)
• Pages: 171-178
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.687.171
• Online since: April 2016
• Authors: Piotr Lacki*
• Keywords: Finite Element Method (FEM), Forming Limit Diagram (FLD), Titanium

References

[1] P. Lacki, J. Adamus, W. Więckowski, J. Winowiecka, Evaluation of drawability of titanium welded sheets, Archives of Metallurgy and Materials 58 (2013) 139–143.

DOI: 10.2478/v10172-012-0164-7

[2] J. Winowiecka, W. Więckowski, M. Zawadzki, Evaluation of drawability of tailor-welded blanks made of titanium alloys grade 2 || grade 5, Computational Materials Science 77 (2013) 108–113.

DOI: 10.1016/j.commatsci.2013.04.026

[3] J. Winowiecka, W. Więckowski, P. Lacki, J. Adamus, Numerical and experimantal analysis of forming titanium welded blanks, Rudy i Metale Nieżelazne 59 (2014) 173–181.

[4] J. Winowiecka, The analysis of springback of titanium sheet after bending, Obróbka Plastyczna Metali XXIV (2013) 219–231.

[5] P. Lacki And J. Adamus, Possibility Of The Increase In Titanium Sheets' Drawability, Key Eng. Mat. 549 (2013) 31–38.

DOI: 10.4028/www.scientific.net/kem.549.31

[6] M. Motyka, J. Sieniawski, W. Ziaja, Microstructural aspects of superplasticity in Ti-6Al-4V alloy, Materials Science and Engineering A 599 57–63.

DOI: 10.1016/j.msea.2014.01.067

[7] J. Adamus, P. Lacki, Investigation of sheet-titanium forming with flexible tool – experiment and simulation, Key Eng. Mat. 549 (2013) 31–38.

[8] J. Adamus, P. Lacki, Analysis of forming titanium welded blanks, Comp. Mater. Sci. (2014).

[9] S.P. Keeler, W.A. Backofen, Plastic instability and fracture in sheets stretched over rigid punches, Trans. ASM 56 (1963).

[10] G.M. Goodwin, Application of strain analysis to sheet metal forming problems in the press shop, Metall Italiana 60 (1698) 764–774.

[11] A. Rezaee-Bazzaz, H. Noori, R. Mahmudi, Calculation of forming limit diagrams using Hill's 1993 yield criterion, International Journal of Mechanical Sciences 53 (2011) 262–270.

DOI: 10.1016/j.ijmecsci.2011.01.007

[12] S. Ahmadi, A.R. Eivani, A. Akbarzadeh, An experimental and theoretical study on the prediction of forming limit diagrams using new BBC yield criteria and M–K analysis, Comp. Mater. Sci. 44 (2009) 1272–1280.

DOI: 10.1016/j.commatsci.2008.08.013

[13] M. Abspoel, M. E. Scholting, J. M. M. Droog, A new method for predicting Forming Limit Curves from mechanical properties, J. Mater. Process. Tech. 213 (2013) 759–769.

DOI: 10.1016/j.jmatprotec.2012.11.022

[14] M. Merklein, A. Kuppert, M. Geiger, Time dependent determination of forming limit diagrams, CIRP Annals - Manufacturing Technology 59 (2010) 295–298.

DOI: 10.1016/j.cirp.2010.03.001

[15] (GOM mbH, ARAMIS v6. 3 and higher - User Manual, 2011).

[16] (GOM mbH, ARAMIS, ARGUS, SVIEW - FLC Computation v6. 1. 1 and higher, 2009).

[17] F. Djavanroodi, A. Derogar, Experimental and numerical evaluation of forming limit diagram for Ti-6Al-4V titanium and Al6061-T6 aluminum alloys sheets, Mater. Design 31 (2010) 4866–4875.

DOI: 10.1016/j.matdes.2010.05.030

[18] P. Lacki, J. Adamus, W. Więckowski, J. Winowiecka, Modelling of stamping process of titanium tailor-welded blanks, Computer Methods in Materials Science 13 (2012) 339–344.

[19] A.S. Atal, M.T. Shete, Formability analysis of deep drawing process by finite element simulation, International Journal of Science and Research 6 (2014) 2153–2156.

[20] K.S. Oh, K.H. Oh, J.H. Jang, D.J. Kim, K.S. Han, Design and analysis of new test method for evaluation of sheet metal formability, J. Mater. Process. Tech. 211 (2011) 695–707.

DOI: 10.1016/j.jmatprotec.2010.12.004

[21] Q. Situ, M. K. Jain, D. R. Metzger, Determination of forming limit diagrams of sheet materials with a hybrid experimental–numerical approach, Int. J. Mech. Sci. 53 (2011) 707–719.

DOI: 10.1016/j.ijmecsci.2011.06.003

[22] J. Adamus, K. Dyja, M. Motyka, Experimental and theoretical determination of forming limit curve, Arch. Metall. Mater. 60/3 (2015) 1881-1885.

DOI: 10.1515/amm-2015-0321