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Vol. 10 (2023)

Impact of DLC Coating Deposition on the Fatigue Strength of Al-7075-T6 Aluminum Alloy

March 29, 2023


Abstract: Al-7075 has interesting mechanical properties but is susceptible to corrosion. Physical Vapor Deposition (PVD) of coatings results in good corrosion resistance and compressive stresses of the order of 1 GPa on the surface of metallic components. However, the impact of PVD films on the strength of Al-7075-T6 is uncertain. This paper provides a summary of the findings of the Authors’ research group in recent years on the fatigue behavior of Al-7075-T6 with and without PVD Diamond-like Carbon (DLC) coating. The results indicated that DLC-coated specimens have lower fatigue strength than uncoated specimens for lives up to about 10000000 cycles. The failure mechanism was determined by observation of the fracture surfaces of the failed specimens. The stress analysis performed confirms the experimental observation, with crack nucleation expected below the surface of coated specimens, where the highest tensile stresses occur during fatigue loading.


  1. Rooy, E.L., 1990. Introduction to aluminum and aluminum alloys, properties and selection: Nonferrous alloys and special-purpose materials, Vol. 2, ASM Handbook, By ASM Handbook Committee, ASM International, p. 3-14.
  2. Feng, T., Ma, B., Chen, F., Zhan, L., Xu, Y., Yang, C., 2022. The effect of temperature on the creep ageing characteristics of Al-Li alloys. Journal of Material Science and Technology Research 9: 65-73.
  3. Li, D., Han, L., Chrysanthou, A., Shergold, M., 2018. Influence of corrosion of self-piercing riveted high strength aluminium alloy joints with button cracks on the mechanical strength. Journal of Material Science and Technology Research, 5: 16-27.
  4. Su, Y., Yang, J., Lin, Z., Qiu, C., Chai, X., Liu, X., Cao, H., Wang, Ouyang, Q., 2022. Structural modeling and thermal conductivity of graphite film reinforced aluminum matrix laminated composites. Journal of Material Science and Technology Research 9: 34-42.
  5. Cayless, R.B.C., 1990. Alloy and temper designation systems for aluminum and aluminum alloys, properties and selection: Nonferrous alloys and special-purpose materials, Vol. 2, ASM Handbook, By ASM Handbook Committee, ASM International, p. 15-28.
  6. Panigrahi, S.K., Jayaganthan, R., 2011. Effect of ageing on microstructure and mechanical properties of bulk, cryorolled, and room temperature rolled Al Al-7075 alloy. J. Alloy. Compd. 509: 9609-9616.
  7. Bray, J.W., 1990. Aluminum mill and engineered wrought products, properties and selection: Nonferrous alloys and special-purpose materials, Vol. 2, ASM Handbook, By ASM Handbook Committee, ASM International, p. 29-61.
  8. VVAA, 1990. Properties of wrought aluminum and aluminum alloys, properties and selection: Nonferrous alloys and special-purpose materials, Vol. 2, ASM Handbook, By ASM Handbook Committee, ASM International, p. 62-122.
  9. Matweb,
  10. Puchi-Cabrera, E.S., Staia, M.H., Lesage, J., Gil, L., Villalobos-Gutiérrez, C., Barbera-Sosa, J.L., Ochoa-Pérez, E.A. and Bourhis, E.L., 2008. Fatigue behavior of AA7075-T6 aluminum alloy coated with ZrN by PVD. Int. J. Fatigue 30: 1220-1230.
  11. Baragetti, S., Gerosa, R., Villa, F., 2016. Step loading corrosion fatigue testing of 7075-T6 WC/C coated specimens in air and methanol. Eng. Fract. Mech. 164: 106-116.
  12. Leng, L., Zhang, Z.J., Duan, Q.Q., Zhang, P., Zhang, Z.F., 2018. Improving the fatigue strength of 7075 alloy through aging. Mat. Sci. Eng. A 738: 24-30.
  13. Silva, G., Rivolta, B., Gerosa, R., Derudi, U., 2013. Study of the SCC behavior of 7075 aluminum alloy after one-step aging at 163 °C. J. Mater. Eng. Perform. 22: 210-214.
  14. Brown, B. F., 1972. Stress-corrosion cracking in high strength steels and in titanium and aluminum alloys, Naval Research Laboratory: Washington, D.C.
  15. Sankaran, K.K., Perez, R., Jata, K.V., 2001. Effects of pitting corrosion on the fatigue behavior of aluminum alloy 7075-T6: modeling and experimental studies. Mater. Sci. Eng. A 297(1-2): 223-229.
  16. Baragetti, S., Borzini, E., Arcieri, E.V., 2018. Effects of environment and stress concentration factor on Ti-6Al-4V specimens subjected to quasi-static loading. Procedia Struct. Integr. 12: 173-182.
  17. Arcieri, E.V., Baragetti, S., Božić, Ž., 2021. Application of design of experiments to foreign object damage on 7075-T6. Procedia Struct. Integrity 31: 22-27.
  18. Baragetti, S., Arcieri, E.V., 2019. Study on a new mobile anti-terror barrier. Procedia Struct. Integr. 24: 91-100.
  19. Baragetti, S., Baryshnikov, A., 2001. Rotary shouldered thread connections: Working limits under combined static loading. J. Mech. Des. 123(3): 456-463.
  20. Baragetti, S., D'Urso, G., 2014. Aluminum 6060-T6 friction stir welded butt joints: Fatigue resistance with different tools and feed rates. J. Mech. Sci. Technol. 28(3): 867-877.
  21. Baragetti, S., Guagliano, M., Vergani, L., 2000. Numerical procedure for shot peening optimization by means of non-dimensional factors. Int. J. Mater. Prod. Technol. 15(1): 91-103.
  22. Baragetti, S., 2013, Corrosion fatigue behaviour of Ti-6Al-4V in methanol environment. Surf. Interface Anal. 45(10): 1654-1658.
  23. Brioua, S., Belmokre, K., Debout, V., Jacquot, P., Conforto, E., Touzain, S., Creus, J., 2022. Influence of spray parameters on the metallurgical and functional properties of HVOF WC based cermets deposited onto low alloy steel. Journal of Material Science and Technology Research 9: 1-10.
  24. Yaqoob, S., Hasan, N., Khalid, S., Akhtar, M. S., 2022. Structural, morphological and optical study of manganese doped FeS (Mackinawite) nanostructures by chemical bath deposition (CBD) technique. Journal of Material Science and Technology Research 9: 24-33.
  25. Silva, T., Ferreira, M., Nascimento, J., Pietro, L., Neto, L. C., Moreira, H., Pereira, L., Leite, N., Gelamo, R., Moreto, J. A., 2022. Development of a low-cost ball-on-flat linear reciprocating apparatus: test validation using Ti-6Al-4V and Ti-6Al-4V/Nb2O5 coatings. Journal of Material Science and Technology Research, 9: 43-52.
  26. Baragetti, S., 2022. Numerical and experimental investigation of the effects of thin hard coatings on the strength of spur gears. Journal of Material Science and Technology Research, 9: 74-86.
  27. Loperena, A., Lehr, I., Saidman, S., 2021. Electrosynthesis of a duplex coating consisting of a cerium-based layer and a polypyrrole film for the corrosion protection of AISI 304 stainless steel. Journal of Material Science and Technology Research, 8: 1-11.
  28. Yan, G., Xiaobing, S., Weiqiang, P., Zhao, Q., Huixiang, X., Huan, L., Xuezhong, F., 2021. Surface coating of Cyclotetramethylenetetranitramine (HMX) particles and its property investigation. Journal of Material Science and Technology Research, 8: 77-81.
  29. Loskutov, S., Ershov, A., Zelenina, E., 2020. Strength and mechanism of adhesion to the substrate layer while applying plasma coatings in oxidizing environments. Journal of Material Science and Technology Research, 7: 1-10.
  30. Bull, S.J., 2006. Physical vapour deposition methods for protection against wear, in: Mellor, B.G. (Ed.), Surface coatings for protection against wear, Woodhead Publishing Ltd., Abington, UK, p. 146.
  31. Srinivasan, N., Bhaskar, L.K., Kumar, R., Baragetti, S., 2018. Residual stress gradient and relaxation upon fatigue deformation of diamond-like carbon coated aluminum alloy in air and methanol environments. Mat. Des. 160: 303-312.
  32. Chang, Y.Z., Tsai, P.H., Li, J.B., Lin, H.C., Jang, J.S.C., Li, C., Chen, G.J., Chen, Y.C., Chu, J.P., Liaw, P.K., 2013. Zr-based metallic glass thin film coating for fatigue-properties. Thin Solid Films 544: 331-334.
  33. Inoue, K., Lyu, S., Deng, G., Kato, M., 1996. Fracture mechanics based evaluation of the effect of the surface treatments on the strength of carburized gears. VDI-Berichte 1320, p. 357.
  34. Su, Y.L., Yao, S.H., Wei, C.S., Wu, C.T., Kao, W.H., 1998. Evaluation on the wear, tension and fatigue behavior of various PVD coated materials. Mater. Lett. 35: 255-260.
  35. Kim, K.R., Suh, C.M., Murakami, R.I., Chung, C.W., 2003. Effect of intrinsic properties of ceramic coatings on fatigue behavior of Cr-Mo-V steels. Surf. Coat. Technol. 171: 15-23.
  36. Baragetti, S., La Vecchia, G.M., Terranova, A., 2003. Fatigue behavior and FEM modeling of thin-coated components. Int. J. Fatigue 25: 1229-1238.
  37. Baragetti, S., La Vecchia, G.M., Terranova, A., 2005. Variables affecting the fatigue resistance of PVD-coated components. Int. J. Fatigue 27: 1541-1550.
  38. Gelfi, M., La Vecchia, G.M., Lecis, N., Troglio, S., 2005. Relationship between through-thickness residual stress of CrN-PVD coatings and fatigue nucleation sites. Surf. Coat. Technol. 192: 263-268.
  39. Baragetti, S., 2007. Fatigue resistance of steel and titanium PVD coated spur gears. Int. J. Fatigue 29: 1893-1903.
  40. Oskouei, R.H., Ibrahim, R.N., 2011. Restoring the tensile properties of PVD-TiN coated Al 7075-T6 using a post heat treatment. Surf. Coat. Technol. 205: 3967-3973.
  41. Baragetti, S., Gelfi, M., La Vecchia, G.M., Lecis, N., 2005. Fatigue resistance of CrN thin films deposited by arc evaporation process on H11 tool steel and 2205 duplex stainless steel, Fatigue Fract. Eng. Mater. Struct. 28: 615-621.
  42. Saini B.S., Gupta, V.K., 2010. Effect of WC / C PVD coating on fatigue behaviour of case carburized SAE8620 steel. Surf. Coat. Technol. 205: 511-518.
  43. Oskouei, R.H., Ibrahim, R.N., 2011. The effect of a heat treatment on improving the fatigue properties of aluminium alloy 7075-T6 coated with TiN by PVD. Procedia Eng. 10: 1936-1942.
  44. Oskouei, R.H., Ibrahim, R.N., 2012. An investigation on the fatigue behaviour of Al 7075-T6 coated with titanium nitride using physical vapour deposition process. Mater. Des. 39: 294-302.
  45. Baragetti, S., Gerosa, R., Villa, F., 2014. WC/C coating protection effects on 7075-T6 fatigue strength in an aggressive environment. Procedia Eng. 74: 33-36.
  46. Puchi-Cabrera, E.S., Villalobos-Gutiérrez, C., Irausquín, I., La Barbera-Sosa, J., Mesmacque, G., 2006. Fatigue behavior of a 7075-T6 aluminum alloy coated with an electroless Ni-P deposit. Int. J. Fatigue 28: 1854-1866.
  47. Elambasseril, J., Ibrahim, R.N., 2011. Determination of interfacial fracture toughness of coatings using circumferentially notched cylindrical substrate. Mater. Sci. Eng. A 529: 406-416.
  48. Oskouei, R.H., Ibrahim, R.N., Barati, M.R., 2012. An experimental study on the characteristics and delamination of TiN coatings deposited on Al 7075-T6 under fatigue cycling. Thin Solid Films 526: 155-162.
  49. Coldwell, H. L., Dewes, R.C., K. Aspinwall, D., Renevier, N.M., Teer, D.G., 2004. The use of soft/lubricating coatings when dry drilling BS L168 aluminium alloy. Surf. Coat. Technol. 177-178: 716-726.
  50. Fukui, H., Okida, J., Omori, N., Moriguchi, H., Tsuda, K., 2004. Cutting performance of DLC coated tools in dry machining aluminum alloys. Surf. Coat. Technol. 187: 70-76.
  51. Grill, A., 1993. Review of the tribology of diamond-like carbon. J. Wear 168:143-153.
  52. Hauert, R., 2004. An overview on the tribological behavior of diamond-like carbon in technical and medical applications. Tribol. Int. 37: 991-1003.
  53. Erdemir, A., Donnet, C., 2006. Tribology of diamond-like carbon films: recent progress and future prospects, J. Phys. D: Appl. Phys. 39: R311-R327.
  54. Pu, J., Wang, J., He, D., Wan, S., 2016. Corrosion and tribocorrosion behaviour of superthick diamond-like carbon films deposited on stainless steel in NaCl solution. Surf. Interface Anal. 48: 360-367.
  55. Zhao, G., Aune, R.E., Espallargas, N., 2016. Tribocorrosion studies of metallic biomaterials: the effect of plasma nitriding and DLC surface modifications. J. Mech. Behav. Biomed Mater. 63: 100-114.
  56. Donnet, C., 1998. Recent progress on the tribology of doped diamond-like and carbon alloy coatings: a review. Surf. Coat. Technol. 100-101: 180-186.
  57. Donnet, C., Fontaine, J., Grill, A., Le Mogne, T., 2001. The role of hydrogen on the friction mechanism of diamond-like carbon films. Tribol. Lett. 9: 137-142.
  58. Robertson, J., 2002. Diamond-like amorphous carbon. Mater. Sci. Eng., R. Rep. 37: 129-281.
  59. Wang, D.-Y., Chang, C.-L., Ho, W.-Y., 1999. Oxidation behavior of diamond-like carbon films. Surf. Coat. Technol. 120-121: 138-144.
  60. Yang; W.J., Choa, Y.-H., Sekino, T., Shim, K.B., Niihara, K., Auh, K.H., 2003. Thermal stability evaluation of diamond-like nanocomposite coatings. Thin Solid Films 476: 49-54.
  61. Zeng, A., Liu, E., Zhang, S., Tan, S.N., Hing, P., Annergren, I.F., Gao, J., 2003. Impedance study on electrochemical characteristics of sputtered DLC films. Thin Solid Films 426: 258-264.
  62. Depner, U., Ellermeier, J., Troßmann, T., Berger, C., Oechsner, M., 2011. The effect of layer structure on corrosion and erosion resistance of thin PVD multilayer films. Int. J. Mater. Res. 08: 1014-1020.
  63. Baragetti, S., Arcieri, E.V., 2022. Effects of thin hard film deposition on fatigue strength of AA7075-T6, Proc. Inst. Mech. Eng., Part C 236(21): 10713-10722.
  64. Lafer S.p.A.,
  65. Baragetti, S., Srinivasan, N., Lalithkumar, B., Kumar, R., 2017. Influence of environment, residual stresses on the fatigue behavior of 7075-T6 aluminum alloy. Key Eng. Mater. 754: 3-6.
  66. Nicholas, T., 2002. Step loading for very high cycle fatigue. Fatigue Fract. Engng. Mater. Struct. 25: 861-869.
  67. Bellows, R.S., Muju, S., Nicholas, T., 1999. Validation of the step test method for generating Haigh diagrams for Ti-6Al-4V. Int. J. Fatigue 21: 687-697.
  68. Baragetti, S., Gerosa, R., Villa, F., 2016. Effects of PVD DLC coating on 7075-T6 fatigue strength at high and low number of cycles. Key Eng. Mater. 713: 50-53.
  69. Arcieri, E.V., Baragetti, S., Borzini, E., 2018. Bending fatigue behavior of 7075-aluminum alloy. Key Eng. Mater. 774: 1-6.
  70. Baragetti, S., Borzini, E., Božić, Ž., Arcieri, E.V., 2019. On the fatigue strength of uncoated and DLC coated 7075-T6 aluminum alloy. Eng. Fail. Anal. 102: 219-225.
  71. Baragetti, S., Božić, Ž., Arcieri, E.V., 2020. Stress and fracture surface analysis of uncoated and coated 7075-T6 specimens under rotating bending fatigue loading. Eng. Fail. Anal. 112: 104512.
  72. Arcieri, E.V., Baragetti, S., 2020. Fatigue behavior of thin hard coated specimens made of 7075. AIP Conference Proceedings 2309: 020027.
  73. Baragetti, S., Gerosa, R., Villa, F., 2013. Fatigue behaviour of thin coated Al 7075 alloy with low temperature PVD coatings. Key Eng. Mater. 577-578: 221-224.
  74. Milella, P.P., 2013. Fatigue and corrosion in metals, Springer, Milan, Italy.