Finite Element Method for Predicting the Cohesive Strength of DLC Film on 316L Stainless Steel by Four Point Bend Test and Validation with Experimental Results

Article Preview

Abstract:

The mechanical performance of DLC coatings on 316L stainless steel deposited by a saddle field fast atom beam source has been evaluated using the four point bend (FPB) test. Two different deposition parameters, pressure and current were varied when depositing the films. Load-displacement measurements were carried out during the bend test to determine the load corresponding to crack initiation. This load designated as the cohesive strength of the coating which is also called the cracking resistance of coating and provides a measure of the strength of the coating. The cohesive strength of the coating was calculated based on elementary beam theory. Scanning Electron Microscopy (SEM) was used to determine the location of the crack. Finite element analysis was used to predict the stress distribution across the coating thickness. The experimental work on FPB tests has been used to support the numerical (finite element) model for the determination and prediction of film cohesive strength. It was observed that at lower deposition current, the cohesive strength increases with increased deposition pressure whereas, for higher deposition current, these values do not increase with increasing deposition pressure. The model takes into account the film’s Young’s modulus, thickness and deposition pressure and current, and has shown that it is capable of predicting film cohesive strength when combined with a theoretical formulation for brittle fracture. It has been observed that the maximum stress develops at the outer surface of the film and propagates through the film-substrate interface. This result has only been validated for films with higher Young’s modulus compared to that of the substrate material.

You might also be interested in these eBooks

Info:

Periodical:

Advanced Materials Research (Volumes 264-265)

Pages:

1823-1831

Citation:

Online since:

June 2011

Export:

Price:

[1] K. Miyoshi, R.L.C. Wu and A. Garscadden: Surf. Coat. Technol. Vol. 54-55 (1992), p.428.

Google Scholar

[2] L. A. Thomson, F. C. Law, N. Rushton and J. Franks: Biomaterials Vol. 12 (1991), p.37.

Google Scholar

[3] K.E. Spear and J.P. Dismukes: Synthetic Diamond: Emerging CVD science and technology, John Wiley & Sons, Inc. NY (1994), p.123.

Google Scholar

[4] Z. Sun, C.H. Lin, Y.L. Lee, J.R. Shi, B.K. Tay and X. Shi: Thin Solid films Vol. 377-378 (2000), p.198.

Google Scholar

[5] T. Zhai, Y. G. Xu, J. W. Martin, A. J. Wilkinson and G. A. D. Briggs: Int. J. Fatigue, Vol. 21 (1999), p.889.

Google Scholar

[6] R.M. Souza, G.G.W. Mustoe and J. J. Moore: Thin Solid Films Vol. 355-356 (1999), p.303.

Google Scholar

[7] W. F. Riely and L. Zachary: Introduction to Mechanics of Materials, John Wiley, NY (1989), p.274.

Google Scholar

[8] O. Unal and D. J. Sordelet: Scripta Mater Vol 42 (2000), p.631.

Google Scholar

[9] M. M. Morshed, D. C. Cameron, B. P. McNamara, and M. S. J. Hashmi: Surf. Coat. Technol. Vol. 169-170 (2003), p.254.

Google Scholar

[10] M. M. Morshed, B. P. McNamara, D. C. Cameron and M. S. J. Hashmi: J. Mater. Proc. Technol. Vol. 143-144 (2003), p.922.

Google Scholar

[11] U. Wiklund, M. Bromark, M. Larsson, P. Hedenqvist and S. Hogmark: Surf. Coat. Technol. Vol. 91 (1997), p.57.

Google Scholar

[12] J. A. Berríos-Ortíz, J. G. La Barbera-Sosa, D. G. Teer and E. S. Puchi-Cabrera: Surf. Coat. Technol. Vol. 179 (2004), p.145.

Google Scholar

[13] Y. Wang and D. Hu: Int. J. Machine Tools and Manufac. Vol. 45 (2005) p.43.

Google Scholar

[14] S. J. Bull and A. K. Korsunsky: Tribol. Int. Vol. 31 (1998), p.547.

Google Scholar