Study of PEO on the fatigue behavior of titanium alloy Ti-6Al-4V

Subject Areas : journal of New Materials

صفا Falahati aghda ¹ (کارشناسی ارشد مهندسی مواد و متالورژی گرایش خوردگی و حفاظت از مواد، واحد یزد، دانشگاه آزاد اسلامی، یزد، ایران)
محمود Hajisafi ² (Department of Metallurgy and Materials Engineering, Yazd Branch, Islamic Azad University, Yazd, Iran)

Received: 2017-04-10 Accepted : 2018-05-08 Published : 2018-04-21

Keywords: Ti-6Al-4V, Fatigue, PEO, Titanium Alloy,

Abstract :

In this study by applying plasma electrolytic oxidation (PEO) coating on titanium alloy Ti-6Al-4V  its fatigue behavior was studied. The results were compared in the presence or absence of the coating. Scanning electron microscopy (SEM) were used to determine the chemical composition of different phases as well as analyzing the microstructure and cracks’ nucleation and propagation and the coating hardness was measured by micro hardness tester. Fatigue test results showed that the fatigue life of the uncoated specimens was longer than the coated specimens. Comparing the images of the fracture surface of the coated specimens and the uncoated specimens in the same surfaces showed that the nucleation of fatigue cracks was appeared in one area in the uncoated specimens while the nucleation of fatigue cracks in coated specimens appeared in multiple areas. According to the microscopic images the coated surface had many pores which causes the nucleation to begin with the coating. The results of the test micro surveys of coverage shows that the hardness of the coating over the layer below it and makes it crack initiation of coverage to begin.

References:

1- C. Leinenbach& D. Eifler, Fatigue and cyclic deformation behaviour of surface-modified titaniumalloys in simulatedphysiological media, Biomaterials,2006, 27, 1200-1208.   

2- I.J. Polmear, Light Alloys from Traditional Alloys toNanocrystals, Fourth Edition, Elsevier, 2006.

3- m. petkovic, S. stojadinovic, R. vasilic, Lj. Zekovic, Characterization of oxide coating formed of tantalum by plasma electrolytic oxidation in 12-tangstosilicic acid, Elsevier (2011) 10590-10594.

4- فریبا مومنی/ سید محمد موسی خوئی/ بررسی خواص پوشش فاز روی ایجاد شده بر روی فولاد کم کربن بر دو الکترولیت سولفاتی و قلیایی توسط روش پلاسمای الکترولیتی اشباع/ مجله مواد نوین/ جلد 6/ شماره3/ بهار 1395.

5- A.L yerokhina, A. shatrovb, V. samsonovb, Oxide ceramic coating on alminium alloys produced by a pulsedbipolar plasma electrolytic oxidation process, surface & coating Technology (2005) 150-157.

6 - A.L. Yerokhin , X. Nie , A. Leyland , A. Matthews , “Characterisation of oxide films produced by plasma electrolytic oxidation of a Ti-6Al-4V alloy”, Surface and Coatings Technology, 2000.

7- J.M. Wheeler , C.A. Collier, J.M. Paillard, J.A. Curran “Evaluation of micromechanical behaviour of plasma electrolytic oxidation (PEO) coatings on Ti-6Al-4V” , Surface & Coatings Technology, 2010.

8- K. Kuromoto , A. Simão , A. Soares , “Titanium oxide films produced on commercially pure titanium by anodic oxidation with different voltages”, Materials Characterization, 2007.

9- Ping Huang, Ke-Wei Xu, Yong Han, “Preparation and apatite layer formation of plasma electrolytic oxidation film on titanium for biomedical application”, Materials Letters, 2005.

10- M. Khorasanian, A. Dehghan, M.H. Shariat, M.E. Bahrololoom, S.Javadpour  “Microstructure and wear resistance of oxide coatings on Ti– 6Al– 4V produced by plasma electrolytic oxidation in an inexpensive electrolyte”, Surface & Coatings Technology, 2011.

11- I. Apachitei, B. Lonyuk, L.E. Fratila-Apachitei, J. Zhou and J. Duszczyk , “Fatigue response of porous coated titanium biomedical alloys”. 2009.

12- S. Aliasghari, P. Skeldon ∗, G.E. Thompson “Plasma electrolytic oxidation of titanium in a phosphate/silicate electrolyte and tribological performance of the coatings”. Applie d Surface Science. 316 (2014) 463–476.

13- Khan, R. H. U., et al. "Residual stresses in plasma electrolytic oxidation coatings on Al alloy produced by pulsed unipolar current." Surface and Coatings Technology 200.5 (2005): 1580-1586.

14- Asquith, D. T., et al. "Effect of combined shot-peening and PEO treatment on fatigue life of 2024 Al alloy." Thin Solid Films 515.3 (2006): 1187-119.