Study on Uniform and Varying Friction Conditions in Superplastic Forming

Abstract:

Surface coatings are crucial for improving the thickness distribution by reducing the interfacial friction between the component and forming die during superplastic forming process. In addition, these coatings act as an oxygen barrier to minimise the formation of alpha case. In this paper, the effect of friction was studied with a single-sheet superplastic forming component using finite-element (FE) analysis and validated through experimental trials. Tensile tests of Ti-6Al-4V were conducted at 900° C according to ASTM E2448 standard, and time-hardening creep power law was used to estimate the material parameters for FE simulation. Herein, two cases were studied. Firstly, a uniform friction condition (one frictional constant) for the whole die surface was studied and a pressure cycle using a strain rate control algorithm was derived using Abaqus. Four different friction constants were studied using the pressure cycle. Low, medium and high fiction coefficients were analysed, along with frictionless conditions. A comparison of FE and experimental results indicated that combining a new coating variant and Boron nitride (BN) achieved similar results to that observed with FE simulation with low friction constant, while results with Boron nitride coating correlated with FE simulation with a medium friction constant. Secondly, a varying friction approach was studied wherein the die surface geometry was segmented and assigned heterogeneous coefficient of friction (COF) values. The obtained FE results suggest that varying friction can introduce slight improvement in the thickness distribution for the selected component geometry.

• Periodical: Key Engineering Materials (Volume 1034)
• Pages: 17-26
• DOI: https://doi.org/10.4028/p-HdqZ3T
• Online since: December 2025
• Authors: Elangovan Parameswaran*, Mark Farell, Ruoyu Huang, William Kerr, Diego Gonzalez, Nicola Zuelli, Marco Bucconi
• Keywords: Finite Element Analysis, Friction Study, Superplastic Forming, Ti-6Al-4V, Varying Friction

References

[1] E. Alabort, D. Putman, and R. C. Reed, "Superplasticity in Ti-6Al-4V: Characterisation, modelling and applications," Acta Mater., 2015.

DOI: 10.1016/j.actamat.2015.04.056

[2] E. Alabort, P. Kontis, D. Barba, K. Dragnevski, and R. C. Reed, "On the mechanisms of superplasticity in Ti-6Al-4V," Acta Mater., 2016.

DOI: 10.1016/j.actamat.2015.12.003

[3] M. I. Albakri, F. S. Jarrar, and M. K. Khraisheh, "Effects of Interfacial Friction Distribution on the Superplastic Forming of AA5083," J. Eng. Mater. Technol., 2011.

DOI: 10.1115/1.4004159

[4] H. Wu, C. Chiu, S. Sheu, S. Lee, and J. Wang, "Effect of Die Surface Roughness on Deformation Characteristics and Cavitation during Blow Forming in a Superplastic 5083 Alloy," Mater. Trans., 2007.

DOI: 10.2320/matertrans.mra2006319

[5] M. H. Shojaeefard, A. Khalkhali, and E. Miandoabchi, "Multi-criteria decision making approach for selecting the best friction distribution in superplastic forming of a vehicle component," Proc. Inst. Mech. Eng. Part E J. Process Mech. Eng., 2014.

DOI: 10.1177/0954408914542858

[6] M. Farrell, M. Drabek, and M. J. Qarni, "A method for the systematic assessment of lubricant performance during superplastic sheet forming: Verfahren zur systematischen Bewertung der Schmierstoffleistung bei der superplastischen Blechumformung," Materwiss. Werksttech., 2017.

DOI: 10.1002/mawe.201700041