Advertisement

Journal of Thermal Spray Technology

, Volume 21, Issue 1, pp 23–40 | Cite as

Residual Strain and Fracture Response of Al2O3 Coatings Deposited via APS and HVOF Techniques

  • R. AhmedEmail author
  • N. H. Faisal
  • A. M. Paradowska
  • M. E. Fitzpatrick
Peer Reviewed

Abstract

The aim of this investigation was to nondestructively evaluate the residual stress profile in two commercially available alumina/substrate coating systems and relate residual stress changes with the fracture response. Neutron diffraction, due to its high penetration depth, was used to measure residual strain in conventional air plasma-sprayed (APS) and finer powder high velocity oxy-fuel (HVOF (θ-gun))-sprayed Al2O3 coating/substrate systems. The purpose of this comparison was to ascertain if finer powder Al2O3 coatings deposited via θ-gun can provide improved residual stress and fracture response in comparison to conventional APS coatings. To obtain a through thickness residual strain profile with high resolution, a partially submerged beam was used for measurements near the coating surface, and a beam submerged in the coating and substrate materials near the coating-substrate interface. By using the fast vertical scanning method, with careful leveling of the specimen using theodolites, the coating surface and the coating/substrate interface were located with an accuracy of about 50 μm. The results show that the through thickness residual strain in the APS coating was mainly tensile, whereas the HVOF coating had both compressive and tensile residual strains. Further analysis interlinking Vickers indentation fracture behavior using acoustic emission (AE) was conducted. The microstructural differences along with the nature and magnitude of the residual strain fields had a direct effect on the fracture response of the two coatings during the indentation process.

Keywords

acoustic emission alumina fracture toughness indentation neutron diffraction residual stress thermal spray coating 

Nomenclatures

a

Average Vickers indentation half-diagonal size

Asg

Ratio of signal gain

c

Average radial crack length c = l a + a

\( d_{hkl} \)

Lattice interplanar spacing

\( d_{hkl}^{0} \)

Strain-free lattice interplanar spacing

E

Acoustic emission energy

Es

Elastic modulus of specimen

Ec,s

Elastic modulus of coating and substrate

Er

Reduced elastic modulus

K1c

Fracture toughness

kAE

AE-based empirical constant

L

Total surface crack length

la

Average surface-radial crack length

P

Indentation load

p1

Center of specimen

p2

Distance from center of specimen

R

Ring-down count

Ra

Surface roughness

hf

Final penetration depth

hmax

Maximum penetration depth

l

Original length

T

Event duration

ΔT

Temperature change

t

Time

Uop

Output signal amplitude

Uip

Input signal amplitude

\( V_{\text{abs}} \)

Absolute voltage

\( V_{\text{t}} \)

Threshold voltage

x

Change in length

Greek Symbols

α

Phase of material composition

αCTE

Coefficient of thermal expansion

γ

Phase of material composition

ɛ

Elastic strain

σ

Stress

ν

Poisson’s ratio

Subscripts

abs

Absolute

c

Coating

f

Final

hkl

Lattice planes

I

Indentation

ip

Input

max

Maximum

op

Output

R

Residual

s

Specimen or surface

Abbreviations

AE

Acoustic emission

APS

Air plasma spray

C

Through thickness coating section

CS

Coating surface

CTE

Coefficient of thermal expansion

dB

Decibel

HVOF

High-velocity oxygen fuel

S

Substrate section near surface

ESEM

Environmental scanning electron microscopy

XRD

X-ray diffraction

Notes

Acknowledgments

The authors acknowledge the provision of beam time at the STFC ISIS Facility, (experiment number RB810413) for the neutron diffraction measurements. Thanks are due to J. Kitamura and S. Osawa, Thermal Spray Materials Department, Fujimi Incorporated, Japan for thermal spraying the specimens. MEF is supported by a grant through The Open University from The Lloyd’s Register Educational Trust, an independent charity working to achieve advances in transportation, science, engineering and technology education, training and research worldwide for the benefit of all.

References

  1. 1.
    P. Fauchais, M. Fukumoto, A. Vardelle, and M. Vardelle, Knowledge Concerning Splat Formation: An invited Review, J. Therm. Spray Technol., 2004, 13, p 337-360CrossRefGoogle Scholar
  2. 2.
    R. Ahmed, H. Yu, V. Stoica, L. Edwards, and J.R. Santisteban, Neutron Diffraction Residual Strain Measurements in Post-treated Thermal Spray Cermet Coatings, Mater. Sci. Eng. A, 2008, 498, p 191-202CrossRefGoogle Scholar
  3. 3.
    R. Ahmed, H. Yu, S. Stewart, L. Edwards, and J.R. Santisteban, Residual Strain Measurements in Thermal Spray Cermet Coatings Via Neutron Diffraction, ASME J. Tribol., 2007, 129, p 411-418CrossRefGoogle Scholar
  4. 4.
    R. Ahmed, N.H. Faisal, S.M. Knupfer, A.M. Paradowska, M.E. Fitzpatrick, K.A. Khor, and J. Cizek, Neutron Diffraction Residual Strain Measurements in Plasma Sprayed Nanostructured Hydroxyapatite Coatings for Orthopaedic Implants, Mater. Sci. Forum, 2010, 652, p 309-314CrossRefGoogle Scholar
  5. 5.
    A. Kulkarni, J. Gutleber, S. Sampath, A. Goland, W.B. Lindquist, H. Herman, A.J. Allen, and B. Dowd, Studies of the Microstructure and Properties of Dense Ceramic Coatings Produced by High-Velocity Oxygen-Fuel Combustion Spraying, Mater. Sci. Eng. A, 2004, 369, p 124-137CrossRefGoogle Scholar
  6. 6.
    T. Itsukaichi, S. Osawa, and R. Ahmed, Proc. Int. Therm. Spray Conf. Florida, C. Moreau and B. Marple, Ed., ASM International, Materials Park, OH, 2003, p 819-824 Google Scholar
  7. 7.
    T. Morishita, S. Osawa, and T. Itsukaichi, HVOF Ceramic Coatings, Proc. Int. Therm. Spray Conf. (Germany), Proc. CD Section: HVOF-Processes and Materials I, ASM International, Materials Park, OH, 2004, p 1-4Google Scholar
  8. 8.
    D.L. Coats and A.D. Krawitz, Effect of Particle Size on Thermal Residual Stress in WC-Co Composites, Mater. Sci. Eng. A, 2003, 359, p 338-342CrossRefGoogle Scholar
  9. 9.
    T.G. Herold, H.J. Prask, and F.S. Biancaniello, Residual Stresses and Elastic Constants in Thermal Deposits, Recent Advances in Experimental Mechanics, E.E. Gdoutos, Ed., in Honor of Isaac M. Daniel, Kluwer Academic Publishers, Dordrecht, Netherlands, 2002, p 507-514Google Scholar
  10. 10.
    S. Ahmaniemi, M. Vippola, P. Vuoristo, T. Mäntylä, M. Buchmann, and R. Gadow, Residual Stresses in Aluminium Phosphate Sealed Plasma Sprayed Oxide Coatings and Their Effect on Abrasive Wear, Wear, 2002, 252, p 614-623CrossRefGoogle Scholar
  11. 11.
    J. Pina, A. Dias, and J.L. Lebrun, Study by X-ray Diffraction and Mechanical Analysis of the Residual Stress Generation During Thermal Spraying, Mater. Sci. Eng. A, 2003, 347, p 21-31CrossRefGoogle Scholar
  12. 12.
    G. Bolelli, L. Lusvarghi, T. Varis, E. Turunen, M. Leoni, P. Scardi, C.L. Cazanza-Ricardo, and M. Barletta, Residual Stresses in HVOF-Sprayed Ceramic Coatings, Surf. Coat. Technol., 2008, 202, p 4810-4819CrossRefGoogle Scholar
  13. 13.
    T. Valente, C. Bartuli, M. Sebastiani, and F. Casadei, Finite Element Analysis of Residual Stress in Plasma-Sprayed Ceramic Coatings, Proc. Inst. Mech. Eng. L J. Mater. Des. Appl., 2004, 218, p 321-330Google Scholar
  14. 14.
    I. Kraus, N. Ganev, G. Gosmanová, H.D. Tietz, L. Pfeiffer, and S. Böhm, Residual Stress Measurement in Alumina Coatings, Mater. Sci. Eng. A, 1995, 199, p L15-L17CrossRefGoogle Scholar
  15. 15.
    O. Kovarık, J. Siegl, N. Nohava, and P. Chraska, Young’s Modulus and Fatigue Behavior of Plasma-Sprayed Alumina Coatings, J. Therm. Spray Technol., 2005, 14, p 231-238CrossRefGoogle Scholar
  16. 16.
    O. Kesler, J. Matejicek, S. Sampath, S. Suresh, T. Gnaeupel-Herold, P.C. Brand, and H.J. Prask, Measurement of Residual Stress in Plasma-Sprayed Metallic, Ceramic and Composite Coatings, Mater. Sci. Eng. A, 1998, 257, p 215-224CrossRefGoogle Scholar
  17. 17.
    V. Luzin, A. Valarezo, and S. Sampath, Through-Thickness Residual Stress Measurement in Metal and Ceramic Spray Coatings by Neutron Diffraction, Mater. Sci. Forum, 2008, 571-572, p 315-320CrossRefGoogle Scholar
  18. 18.
    R. Ahmed, N.H. Faisal, R.L. Reuben, A. Paradowska, M. Fitzpatrick, J. Kitamura, and S. Osawa, Neutron Diffraction Residual Strain Measurements in Alumina Coatings Deposited Via Air Plasma and High Velocity Oxy-Fuel Techniques, J. Phys: CS, 2010, 251, art no. 012051Google Scholar
  19. 19.
    S. Safai, H. Herman, and K. Ono, Acoustic Emission Study of Thermal-Sprayed Oxide Coatings, Am. Ceram. Soc. Bull., 1979, 58, p 624Google Scholar
  20. 20.
    S.L. Ajit Prasad, M.M. Mayuram, and R. Krishnamurthy, Response of Plasma-Sprayed Alumina-Titania Composites to Static Indentation Process, Mater. Lett., 1999, 41, p 234-240CrossRefGoogle Scholar
  21. 21.
    N.H. Faisal, R.L. Reuben, and R. Ahmed, An Improved Measurement of Vickers Indentation Behaviour Through Enhanced Instrumentation, Meas. Sci. Technol., 2011, 22, art no. 015703 (18 pp)Google Scholar
  22. 22.
    N.H. Faisal, J.A. Steel, R. Ahmed, and R.L. Reuben, The Use of Acoustic Emission to Characterize Fracture Behavior During Vickers Indentation of HVOF Thermally Sprayed WC-Co Coatings, J. Therm. Spray Technol., 2009, 18, p 525-535CrossRefGoogle Scholar
  23. 23.
    N.H. Faisal, “Acoustic Emission Analysis for Quality Assessment of Thermally Sprayed Coatings,” PhD thesis, Heriot-Watt University, 2009Google Scholar
  24. 24.
    N.H. Faisal, R. Ahmed, and R.L. Reuben, Indentation Testing and its Acoustic Emission Response: Applications and Emerging Trends, Int. Mater. Rev., 2011, 56, p 98-142CrossRefGoogle Scholar
  25. 25.
    “Standard Test Method for Vickers Hardness of Metallic Materials,” ASTM E 92-82, 1992Google Scholar
  26. 26.
    W.C. Oliver and G.M. Pharr, An Improved Technique for Determining Hardness and Elastic Modulus Using Load and Displacement Sensing Indentation Experiments, J. Mater. Res., 1992, 7, p 1564-1583CrossRefGoogle Scholar
  27. 27.
    M.R. Daymond, M.A.M. Bourke, R.B. Von Dreele, B. Clausen, and T. Lorentzen, Use of Rietveld Refinement for Elastic Macrostrain Determination and for Evaluation of Plastic Strain History From Diffraction Spectra, J. Appl. Phys., 1997, 82, p 1554-1562CrossRefGoogle Scholar
  28. 28.
    L. Edwards, Near-Surface Stress Measurement Using Neutron Diffraction, Analysis of Residual Stress Using Neutron and Synchrotron Radiation, M.E. Fitzpatrick and A. Lodini, Ed., Taylor & Francis, London, 2003, p 233 CrossRefGoogle Scholar
  29. 29.
    P.J. Withers, M.W. Johnson, and J.S. Wright, Neutron Strain Scanning Using a Radially Collimated Diffracted Beam, Physica B, 2000, 292, p 273-285CrossRefGoogle Scholar
  30. 30.
    H. Vallen, AE Testing Fundamentals, Equipment, Applications, NDT.net 7, http://www.ndt.net/article/v07n09/05/05.htm, 2002
  31. 31.
    K. Nihara, R. Morena, and D.P. Hasselman, Evaluation of K 1c of Brittle Solids by the Indentation Method with Low Crack-to-Indent Ratios, J. Mater. Sci. Lett., 1982, 1, p 13-16CrossRefGoogle Scholar
  32. 32.
    K.M. Liang, G. Orange, and G. Fantozzi, Evaluation by Indentation of Fracture Toughness of Ceramic Materials, J. Mater. Sci., 1990, 25, p 207-214CrossRefGoogle Scholar
  33. 33.
    D.K. Shetty, I.G. Wright, P.N. Mincer, and A.H. Clauer, Indentation Fracture of WC-Co Cermets, J. Mater. Sci., 1985, 20, p 1873-1882CrossRefGoogle Scholar
  34. 34.
    S. Guicciardi, A. Balbo, D. Sciti, C. Melandri, and G. Pezzotti, Nanoindentation Characterization of SiC-Based Ceramics, J. Eur. Ceram. Soc., 2007, 27, p 1399-1404CrossRefGoogle Scholar
  35. 35.
    S. Hao, C.J. Li, and G.J. Yang, Influence of Deposition Temperature on the Microstructures and Properties of Plasma-Sprayed Al2O3 Coatings, J. Therm. Spray Technol., 2011, 20, p 160-169CrossRefGoogle Scholar
  36. 36.
    R. Mušálek, O. Kovárík, and J. Matejícek, In Situ Observation of Crack Propagation in Thermally Sprayed Coatings, Surf. Coat. Technol., 2010, 205, p 1807-1811CrossRefGoogle Scholar
  37. 37.
    K.S. Forcey and I. Iordanova, Texture and Residual Stresses in Thermally Sprayed Coatings, Surf. Coat. Technol., 1997, 91, p 174-182CrossRefGoogle Scholar
  38. 38.
    K. Shinoda, M. Demura, H. Murakami, S. Kuroda, and S. Sampath, Characterization of Crystallographic Texture in Plasma-Sprayed Splats by Electron-Backscattered Diffraction, Surf. Coat. Technol., 2010, 204, p 3614-3618CrossRefGoogle Scholar
  39. 39.
    S. Kuroda, Properties and Characterization of Thermal Sprayed Coatings—A Review of Recent Research, Proc 15th Int. Therm. Spray Conf. (Nice), 1998, p 539-550Google Scholar
  40. 40.
    T.Y. Tsui, W.C. Oliver, and G.M. Pharr, Influence of Stress on the Measurement of Mechanical Properties Using Nanoindentation: Part I. Experimental Studies in an Aluminum Alloy, J. Mater. Res., 1996, 11, p 752-759CrossRefGoogle Scholar
  41. 41.
    T. Gnaeupel-Herold, H.J. Prask, J. Barker, F.S. Biancaniello, R.D. Jiggetts, and J. Matejicek, Microstructure, Mechanical Properties, and Adhesion in IN625 Air Plasma Sprayed Coatings, Mater. Sci. Eng. A, 2006, 421, p 77-85CrossRefGoogle Scholar
  42. 42.
    R. Knight and R.W. Smith, Thermal Spray Coatings: Research, Design, and Applications, C.C. Berndt and T.F. Bernecki, Ed., ASM International, Materials Park, OH, 1993, p 607-612 Google Scholar
  43. 43.
    T.C. Totemeier and J.K. Wright, Residual Stress Determination in Thermally Sprayed Coatings—A Comparison of Curvature Models and X-ray Techniques, Surf. Coat. Technol., 2006, 200, p 3955-3962CrossRefGoogle Scholar
  44. 44.
    S.C. Gill, “Residual Stress in Plasma Sprayed Deposits,” PhD Thesis, Cambridge University, 1993Google Scholar
  45. 45.
    H.M. Soliman and A.F. Waheed, Effect of Differential Thermal Expansion Coefficient on Stresses Generated in Coating, J. Mater. Sci. Technol., 1999, 15, p 457-462Google Scholar
  46. 46.
  47. 47.
    B.R. Lawn and R. Wilshaw, Review, Indentation Fracture: Principles and Applications, J. Mater. Sci., 1975, 10, p 1049-1081CrossRefGoogle Scholar
  48. 48.
    A.A. Griffith, The Phenomena of Rupture and Flow in Solids, Philos. Trans. R. Soc. Lond. A, 1920, 221, p 163-198CrossRefGoogle Scholar
  49. 49.
    A.P. Buang, R. Liu, X.J. Wu, and M.X. Yao, Cracking Analysis of HVOF Coatings Under Vickers Indentation, J. Coat. Technol. Res., 2008, 5, DOI  10.1007/s11998-008-9106-8.
  50. 50.
    V. Stoica, R. Ahmed, T. Itsukaichi, and S. Tobe, Sliding Wear Evaluation of Hot Isostatically Pressed (HIPed) Thermal Spray Cermet Coatings, Wear, 2004, 257, p 1103-1124CrossRefGoogle Scholar
  51. 51.
    C.B. Ponton and R.D. Rawlings, Vickers Indentation Fracture Toughness Test: Part 1. Review of Literature and Formulation of Standardised Indentation Toughness Equations, Mater. Sci. Technol., 1989, 5, p 865-872Google Scholar
  52. 52.
    M. Factor and I. Roman, Microhardness as a Simple Means of Estimating Relative Wear Resistance of Carbide Thermal Spray Coatings: Part 1. Wear Resistance of Cemented Carbide Coatings, J. Therm. Spray Technol., 2002, 11, p 468-481CrossRefGoogle Scholar
  53. 53.
    H. Luo, D. Goberman, L. Shaw, and M. Gell, Indentation Fracture Behaviour of Plasma-Sprayed Nanostructured Al2O3-13 wt. %TiO2 Coatings, Mater. Sci. Eng. A, 2003, 346, p 237-245CrossRefGoogle Scholar
  54. 54.
    P. Ostojic and R. McPherson, Indentation Toughness Testing of Plasma Sprayed Coatings, Mater. Forum, 1987, 10, p 247-255Google Scholar
  55. 55.
    K. Kapoor, A. Ahmad, A. Laksminarayana, and G.V.S. Hemanth Rao, Fracture Properties of Sintered UO2 Ceramic Pellets With Duplex Microstructure, J. Nucl. Mater., 2007, 366, p 87-98CrossRefGoogle Scholar
  56. 56.
    J. Akbari, Y. Saito, T. Hanaoka, and S. Enomoto, Acoustic Emission and Deformation Mode in Ceramics During Indentation, JSME Int. J. Ser. A Mech. Mater. Eng., 1994, 37, p 488-494Google Scholar
  57. 57.
    A.K. Ray, G. Das, N.K. Mukhopadhyay, D.K. Bhattacharya, E.S. Dwarakadasa, and N. Parida, Studies on Indentation Fracture Toughness on Ceramic and Ceramic Composite Using Acoustic Emission Technique, Bull. Mater. Sci., 1999, 22, p 25-32CrossRefGoogle Scholar
  58. 58.
    J.M. Jungk, B.L. Boyce, T.E. Buchheit, T.A. Friedmann, D. Yang, and W.W. Gerberich, Indentation Fracture Toughness and Acoustic Energy Release in Tetrahedral Amorphous Carbon Diamond-Like Thin Films, Acta Mater., 2006, 54, p 4043-4052CrossRefGoogle Scholar
  59. 59.
    X. Chen, J. Yan, and A.M. Karlsson, On the Determination of Residual Stress and Mechanical Properties by Indentation, Mater. Sci. Eng. A, 2006, 416, p 139-149CrossRefGoogle Scholar
  60. 60.
    J. Jang, Estimation of Residual Stress by Instrumented Indentation: A Review, J. Ceram. Process. Res., 2009, 10, p 391-400Google Scholar
  61. 61.
    P.J. Withers and H.K.D.H. Bhadeshia, Residual Stress Part 1—Measurement Techniques, Mater. Sci. Technol., 2001, 17, p 355-365CrossRefGoogle Scholar

Copyright information

© ASM International 2011

Authors and Affiliations

  • R. Ahmed
    • 1
    • 2
    Email author
  • N. H. Faisal
    • 1
    • 2
  • A. M. Paradowska
    • 3
  • M. E. Fitzpatrick
    • 4
  1. 1.School of EPSHeriot-Watt UniversityEdinburghUK
  2. 2.College of EngineeringAlfaisal UniversityRiyadhKingdom of Saudi Arabia
  3. 3.Rutherford Appleton LaboratoryISISDidcotUK
  4. 4.Materials EngineeringThe Open UniversityMilton KeynesUK

Personalised recommendations