Modares Mechanical Engineering

Modares Mechanical Engineering

Study the effect of electrical discharge machining (EDM) on residual stress and corrosion resistance of Ti-6Al-4V alloy

Authors
hamed Tavanaei 1
behnam khosrozadeh 2
1 کارشناشی ارشد دانشگاه تبریز دانشکده مکانیک
2 Department of Mechanical Engineering, Malekan Branch, Islamic Azad University, Malekan, Iran
Abstract
Ti-6Al-4V alloy due to excellent mechanical properties mainly is used in the aerospace, automobile and biomedical industries. Electrical discharge machining (EDM) are used extensively for machining of this alloy. Due to the thermoelectric nature of this process, unwanted changes happen on machined surface such as development of residual stresses and the change in the corrosion resistance. The aim of this study is the experimental investigation of the effect of input parameters (discharge current and pulse on time) on the amount and distribution of residual stresses and corrosion resistance changes of the machined surface in EDM process of Ti-6Al-4V alloy. For this purpose, samples of Ti-6Al-4V alloy were machined by EDM process and residual stresses induced successive sparks in different setting (different discharge currents and pulses on time) were measured by nanoindentation method and SEM images of machined surface used to better assess of samples surface integrity. TOFL measurement method used to determine the corrosion resistance of the samples. Results indicate that at this process tensile stresses is formed on surface and mentioned stresses increase with depth initially and after reaching a maximum dropping out and eventually leads to pressure stress. By increasing pulse on time and discharge current, maximum tension residual stress only slightly increases and is near ultimate tensile strength of work piece material. Comparison of corrosion results indicated that the corrosion resistance of EDMed samples, was less than the not machined specimens.
Keywords
Electrical discharge machining
Residual Stress
Nanoindentation
corrosion resistance
Ti-6Al-4V
[1] A. Descoeudres, Characterization of Electrical Discharge Machining Plasmas, PhD Thesis, EPFL Lausanne, 2006.
[2] J. Y. Kao, C. C. Tsao, S. S. Wang, C. Y. Hsu, Optimization of the EDM parameters on machining Ti–6Al–4V with multiple quality characteristics, Advanced Manufacturing Technology, Vol. 47, No. 1-4, pp. 395-402, 2010.
[3] A. Hascalık, U. Caydas, A comparative study of surface integrity of Ti–6Al– 4V alloy machined by EDM and AECG, Materials Processing Technology, Vol. 190, No. 1-3, pp. 173-180, 2007.
[4] . Ekmekci, Residual stresses and white layer in electric discharge machining (EDM), Applied Surface Science, Vol. 253, No. 23, pp. 9234-9240, 2007.
[5] N. S. Rossini, M. Dassisti, K. Y. Benyounis, A. G. Olabi, Methods of measuring residual stresses in components, Materials and Design, Vol. 35, No. 1, pp. 572-588, 2012.
[6] L. Zhu, B. Xu, H. Wang, C. Wang, Measurement of residual stress in quenched 1045 steel by the nanoindentation method, Materials Characterization, Vol. 61, No. 12, pp. 1359-1362, 2010.
[7] J. E. Wyatt, J. T. Berry, A new technique for the determination of superficial residual stresses associated with machining and other manufacturing processes, Materials Processing Technology, Vol. 171, No. 1, pp. 132-140, 2006.
[8] F. Díaz, C. Mammana, A. Guidobono, Evaluation of residual stresses induced by high speed milling using an indentation method, Modern Mechanical Engineering, Vol. 2, No. 4, pp. 143-150, 2012.
[9] C. A. Charitidis, D. A. Dragatogiannis, E. P. Koumoulos, I. A. Kartsonakis, Residual stress and deformation mechanism of friction stir welded aluminum alloys by nanoindentation, Materials Science and Engineering, Vol. A 540, pp. 226-234, 2012.
[10] H. Sidhom, F. Ghanem, T. Amadou, G. Gonzalez, C. Braham, Effect of electro discharge machining (EDM) on the AISI316L SS white layer microstructure and corrosion resistance, The Advanced Manufacturing Technology, Vol. 65, No 1-4, pp. 141-153, 2013.
[11] J. C. Rebelo, A. M. Dias, D. Kremer, J. L. Lebrun, Influence of EDM pulse energy on the surface integrity of martensitic steels, Materials Processing Technology, Vol. 84, No. 1-3, pp. 90-96, 1998.
[12] V. G. Navas, I. Ferreres, J. A. Maranon, C.G. Rosales, J. G. Sevillano, Electro-discharge machining (EDM) versus hard turning and grinding— Comparison of residual stresses and surface integrity generated in AISI O1 tool steel, Materials Processing Technology, Vol. 195, No. 1-3, pp. 186-194, 2008.
[13] J. C. Rebelo, M. Kommeier, A. C. Batista, A. M. Dias, Residual stress after EDM-FEM study and measurement results, Materials Science Forum, Vol. 404-407, pp. 159-164, 2002.
[14] F. Ghanem, C. Braham, H. Sidhom, Influence of steel type on electrical discharge machined surface integrity, Materials Processing Technology, Vol. 142, No. 1, pp. 163-173, 2003.
[15] B. Ekmekci, O. Elkoca, A. E. Tekkaya, A. Erden, Residual stress state and hardness depth in electric discharge machining: De-Ionized water as dielectric liquid, Machine Science and Technology, Vol. 9, No. 1, pp. 39-61, 2005.
[16] N. B. Salah, F. Ghanem, K. B. Atig, Thermal and mechanical numerical modelling of electric discharge machining process, Numerical Methods in Biomedical Engineering, Vol. 24, No. 12, pp. 2021-2034, 2008.
[17] M. R. Shabgard, B. Khosrozadeh, Study the effect of ultrasonic assisted electrical discharge machining process on residual stress and hardness of Ti6Al-4V alloy, Modares Mechanical Engineering, Vol. 16, No. 8, pp. 169- 176, 2016. (in Persian فارسی(
[18] A. Ntasi, W. D. Mueller, G. Eliades, S. Zinelis, The effect of Electro Discharge Machining (EDM) on the corrosion resistance of dental alloys, Dental Materials, Vol. 26, No. 12, pp. e237–e245, 2010.
[19] Y. Uno, A. Okada, K. Uemura, P. Raharjo, T. Furukawa, K. Karato, Highefficiency finishing process for metal mould by large-area electron beam irradiation, Precision Engineering, Vol. 29, No. 4, pp. 449-455, 2005.
[20] B. Jabbaripour, M. H. Sadeghi, M. R. Shabgard, H. Faraji, Investigating surface roughness, material removal rate and corrosion resistancein PMEDM of γ-TiAl intermetallic, Manufacturing Processes, Vol. 15, No. 1, pp. 56-68, 2013.
[21] G. Lütjering, J. C. Williams, Titanium, 2nd edition, pp. 115-125, Berlin, Springer, 2007.
[22] M. G. Fontana, Corrosion Engineering, third edition, pp. 499-502, Sinagapore, McGraw Hill, 1987.
[23] A. W. Warren, Y. B. Guo, M. L. Weaver, The influence of machining induced residual stress and phase transformation on the measurement of subsurface mechanical behavior using nanoindentation, Surface & Coatings Technology, Vol. 200, No. 11, pp. 3459– 3467, 2006.
[24] F. Karimzadeh, M. Heidarbeigy, A. Saatchi, Effect of heat treatment on corrosion behavior of Ti–6Al–4V alloy weldments, Materials Processing Technology, Vol. 206, No. 1-3, pp. 388-394, 2008.
Modares Mechanical Engineering
Volume 18, Issue 3
May 2018
Pages 171-178