Method for Calculating the Parameters of Superplasticity of Titanium Alloys Based on the Results of Test Forming into a Rectangular Matrix at Constant Pressure

We propose a procedure to determine the strain rate sensitivity index of a superplastic material from the results of bulge forming of a long thin rectangular membrane under constant pressure of inertia gas. In contrast to other known procedures, the method suggested takes into consideration the presence of entry radius in the matrix set used. The mathematical model of the technological process is developed based on the main assumptions of the thin shell theory. To validate the procedure suggested the finite element analysis is fulfilled using the software package ANSYS 10 ED. Experimental approbation of the method suggested is carried out on the titanium alloys Ti-6Al-4V, a good agreement is achieved. It is shown that taking into account the influence of the entry radius allows to improve considerably the accuracy for finite element modelling. We draw the conclusion that the procedure developed may be recommended for practical usage to determine the superplastic parameters of thin sheet superplastic materials.

Keywords

superplastic forming; rheological parameters; rectangular matrix; entry radius; ANSYS.

References

1. Perez-Prado M.T., Kassner M.E. Fundamentals of Creep in Metals and Alloys. Amsterdam, Elsevier Science, 2015.
2. Smirnov O.M. Obrabotka metallov v sostoyanii sverkhplastichnosti [Superplastic Metal Working Techniques]. Moscow, Mashinostroenie, 1979. (in Russian)
3. Safiullin R.V., Vasin R.A., Enikeev F.U. Determination of the Parameters of Superplastic Forming for Long Rectangular thin Sheet Titanium Alloy Ti-6Al-4V. Acta Metallurgica Sinica, 2000, vol. 13, pp. 567-573.
4. Kaibyshev O.A. Sverkhplastichnost' promyshlennykh splavov. [Superplasticity of Industrial Alloys]. Moscow, Metallurgy, 1984. (in Russian)
5. Enikeev F.U., Kruglov A.A. An Analysis of the Superplastic Forming of a Thin Circular Diaphragm. International Journal of Mechanical Sciences, 1995, vol. 37, no. 5, pp. 473-483.
6. Vasin R.A., Enikeev F.U., Kruglov A.A., Safiullin R.V. [Identification of Defining Relations According to the Results of Technological Experiments]. Mechanics of Solids, 2003, no. 2, pp. 111-123. (in Russian)
7. Aksenov S.A., Chumachenko E.N., Kolesnikov A.V., Osipov S.A. Determination of Optimal Gas Forming Conditions from Free Bulging Tests at Constant Pressure. Journal of Materials Processing Technology, 2015, pp. 158-164.
8. Jarrar F.S., Abu-Farha F.K., Hector L G., Khraisheh M.K. Simulation of High-Temperature AA5083 Bulge Forming with a Hardening/Softening Material Model. Journal of Materials Engineering and Performance, 2009, vol. 18, no. 7, pp. 863-870. DOI: 10.1007/s11665-008-9322-5
9. Carrino L., Giuliano G., Palmieri C. On the Optimization of Superplastic Forming Processes by the Finite-Element Method. Journal of Materials Processing Technology, 2003, vol. 143-144, pp. 373-377. DOI: 10.1016/S0924-0136(03)00423-0
10. Malinin N.N., Romanov K.I. [An Investigation of the Process of Gasostatic Forming of a Long Membrane]. Soviet Machine Science, 1982, no. 4, pp. 98-101. (in Russian)
11. Ghosh A.K., Hamilton C.H. Influence of Material Parameters and Microstructure on Superplastic Forming. Metallurgical Transactions, 1982, vol. 13, no. 5, pp. 733-743.
12. Malinin N.N. Polzuchest v obrabotke metallov [Creep in Metal Working]. Moscow, Mashinostroenie, 1986. (in Russian)
13. Ganieva V.R., Kutlueva A.I., Enikeev F.U. Method to Determine the Optimal Conditions for Superplastic Flow. Problems of Mechanical Engineering and Automation, 2012, no. 1, pp. 132-138. (in Russian)
14. Safiullin R.V., Enikeev F.U. Calculation of Regimes for Superplastic Forming of an Elongated Rectangular Membrane. Forging and Stamping Production. Material Working by Pressure, 2001, no. 3, pp. 35-40. (in Russian)