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In-situ study of microscale fracture of diffusion aluminide bond coats: Effect of platinum

Published online by Cambridge University Press:  28 September 2015

Balila Nagamani Jaya ,
Sanjit Bhowmick ,
S.A. Syed Asif  and
Vikram Jayaram
Balila Nagamani Jaya*
Affiliation:
Department of Materials Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
Sanjit Bhowmick
Affiliation:
Hysitron Inc., Minneapolis, Minnesota 55344, USA
S.A. Syed Asif
Affiliation:
Hysitron Inc., Minneapolis, Minnesota 55344, USA
Vikram Jayaram
Affiliation:
Department of Materials Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
*
a)Address all correspondence to this author. e-mail: jaya86@gmail.com
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Abstract

The influence of Pt layer thickness on the fracture behavior of PtNiAl bond coats was studied in situ using clamped micro-beam bend tests inside a scanning electron microscope (SEM). Clamped beam bending is a fairly well established micro-scale fracture test geometry that has been previously used in determination of fracture toughness of Si and PtNiAl bond coats. The increasing amount of Pt in the bond coat matrix was accompanied by several other microstructural changes such as an increase in the volume fraction of α-Cr precipitate particles in the coating as well as a marginal decrease in the grain size of the matrix. In addition, Pt alters the defect chemistry of the B2-NiAl structure, directly affecting its elastic properties. A strong correlation was found between the fracture toughness and the initial Pt layer thickness associated with the bond coat. As the Pt layer thickness was increased from 0 to 5 µm, resulting in increasing Pt concentration from 0 to 14.2 at.% in the B2-NiAl matrix and changing α-Cr precipitate fraction, the initiation fracture toughness (KIC) was seen to rise from 6.4 to 8.5 MPa·m1/2. R-curve behavior was observed in these coatings, with KIC doubling for a crack propagation length of 2.5 µm. The reasons for the toughening are analyzed to be a combination of material's microstructure (crack kinking and bridging due to the precipitates) as well as size effects, as the crack approaches closer to the free surface in a micro-scale sample.

Keywords

aluminide bond coatsfracture toughnesscrack propagationfocused ion beam machiningnanoindentationaero-engine components
Type
Articles
Information
Journal of Materials Research , Volume 30 , Issue 21 , 13 November 2015 , pp. 3343 - 3353
Copyright
Copyright © Materials Research Society 2015 

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Footnotes

b)

Present address: Max Planck Institute for Iron Research, Max Planck Strasse-1, Duesseldorf 40237, Germany.

Contributing Editor: Yang-T. Cheng

References

REFERENCES

Jaya, B.N., Jayaram, V., and Biswas, S.K.: A new method for fracture toughness determination of graded (Pt,Ni)Al bond coats by microbeam bend tests. Philos. Mag. 92, 3326–3345 (2012).Google Scholar
Das, D.K.: Microstructure and high temperature oxidation behavior of Pt-modified aluminide bond coats on Ni-base superalloys. Prog. Mater. Sci. 58, 151–182 (2013).Google Scholar
Gleeson, B., Wang, W., Hayashi, S., and Sordelet, D.: Effects of platinum on the interdiffusion and oxidation behavior of Ni–Al based alloys. Mater. Sci. Forum 461–464, 213–222 (2004).CrossRefGoogle Scholar
Pan, D., Chen, M.W., Wright, P.K., and Hemker, K.J.: Evolution of a diffusion aluminide bond coat for thermal barrier coatings during thermal cycling. Acta Mater. 51, 2205–2217 (2003).Google Scholar
Riethmüller, J., Dehm, G., Affeldt, E.E., and Arzt, E.: Microstructure and mechanical behavior of Pt-modified NiAl diffusion coatings. Int. J. Mater. Res. 97, 689–698 (2006).Google Scholar
Passilly, B., Kanoute, P., Leroy, F.H., and Mevrel, R.: High temperature instrumented microindentation: Applications to thermal barrier coating constituent materials. Philos. Mag. 86, 5739–5752 (2006).Google Scholar
Zhang, M. and Heuer, A.H.: Spatially varying microhardness in a platinum-modified nickel aluminide bond coat in a thermal barrier coating system. Scr. Mater. 54, 1265–1269 (2006).Google Scholar
Alam, M.Z., Kamat, S.V., Jayaram, V., and Das, D.K.: Micromechanisms of fracture and strengthening in free-standing Pt-aluminide bond coats under tensile loading. Acta Mater. 67, 278–296 (2014).Google Scholar
Miracle, D.B. and Darolia, R.: NiAl and its Alloys. Intermetallic Compounds (John Wiley & Sons, Chichester, UK, 1995), chapter 3, p. 55.Google Scholar
Noebe, R.D., Bowman, R.R., and Nathal, M.V.: Physical and mechanical properties of the B2 compound NiAl. Int. Mater. Rev. 38, 193–232 (1993).Google Scholar
Iqbal, F., Ast, J., Goeken, M., and Durst, K.: In-situ microcantilever tests to study fracture properties of NiAl single crystals. Acta Mater. 60, 1193–1200 (2012).CrossRefGoogle Scholar
Ast, J., Przybilla, T., Maier, V., Durst, K., and Goeken, M.: Microcantilever bending experiments in NiAl—Evaluation, size effects, and crack tip plasticity. J. Mater. Res. 29, 2129–2140 (2014).CrossRefGoogle Scholar
Jaya, B.N., Kirchlechner, C., and Dehm, G.: Can microscale fracture tests provide reliable fracture toughness values? A case study in silicon. J. Mater. Res. 30, 686–698 (2015).Google Scholar
Jiang, C., Besser, M.F., Sordelet, D.J., and Gleeson, B.: A combined first-principles and experimental study of the lattice site preference of Pt in B2 NiAl. Acta Mater. 53, 2101–2109 (2005).Google Scholar
Cullity, B.D.: Elements of X Ray Diffraction (Addison-Wesley Publishing Company, Inc., Reading, MA, 1956).Google Scholar
Oliver, W.C. and Pharr, G.M.: An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J. Mater. Res. 7, 1564–1583 (1992).Google Scholar
Jaya, B.N. and Jayaram, V.: Crack stability in edge notched clamped beam specimen: Modeling and experiments. Int. J. Fract. 188, 213–228 (2014).Google Scholar
Jaya, B.N., Bhowmick, S., S Asif, S.A., Warren, O.L., and Jayaram, V.: Optimisation of clamped beam geometry for fracture toughness testing of micron-scale samples. Philos. Mag. 95, 1945–1966 (2015).Google Scholar
Anstis, G.R., Chantikul, P., Lawn, B.R., and Marshall, D.B.: A critical evaluation of indentation techniques for measuring fracture toughness: I, direct crack measurements. J. Am. Ceram. Soc. 64(9), 533–538 (1981).Google Scholar
Baither, D., Ernst, F., Wagner, T., Rühle, M., Bartsch, M., and Messerschmidt, U.: Micromechanisms of fracture in NiAl studied by in situ straining experiments in an HVEM. Intermetallics 7, 479–489 (1999).Google Scholar
Webler, R., Krottenthaler, M., Neumeier, S., Durst, K., and Göken, M.: Local fracture toughness and residual stress measurements on NiAl bond coats by micro cantilever and FIB based bar milling tests. In TMS Conference Proceedings on International Symposium Superalloys; TMS: Warrendale, PA, 2012; p. 93.Google Scholar
Fox, A.G. and Tabbernor, M.A.: The bonding charge density of β′NiAl. Acta Metall. Mater. 39, 669–678 (1991).Google Scholar
Ternes, K., Xie, Z.Y., and Farkas, D.: Atomistic modelling of stoichiometry effects on dislocation core structure in NiAl. Mater. Sci. Eng., A 192–193, 125–133 (1995).Google Scholar
Kogachi, M., Tanahashi, M.T., Shirai, Y., and Yamaguchi, M.: Determination of vacancy concentration and defect structure in the B2 type NiAl β-phase alloys. Scr. Mater. 34, 243–248 (1996).Google Scholar
Jiang, C., Sordelet, D.J., and Gleeson, B.: Effects of Pt on the elastic properties of B2 NiAl: A combined first-principles and experimental study. Acta Mater. 54, 2361–2369 (2006).Google Scholar
Feng, J., Xiao, B., Chen, J., Dua, Y., Yua, J., and Zhou, R.: Stability, thermal and mechanical properties of PtxAly compounds. Mater. Des. 32, 3231–3239 (2011).Google Scholar
Tian, J.S., Han, G.M., Wei, H., Zheng, Q., Jin, T., Sun, X.F., and Hu, Z.Q.: Effects of alloying elements on the electronic structure and ductility of NiAl compounds investigated by X-ray absorption fine structure. Philos. Mag. 93, 2161–2171 (2013).Google Scholar
Dieter, G.E.: Mechanical Metallurgy (Mc Graw Hill, NY, 1961).Google Scholar
www.periodictable.com.Google Scholar
Yu, R. and Hou, P.Y.: First principles calculation of the effect of Pt on NiAl surface energy and the site preference of Pt. Appl. Phys. Lett. 91, 011907-1-011907-3 (2007).Google Scholar
Cotton, J.D., Noebe, R.D., and Kaufman, M.J.: The effects of chromium on NiAl intermetallic alloys: Part II. Slip systems. Intermetallics 1, 117–126 (1993).Google Scholar
Han, C.K.: Precipitation behavior of B2-ordered aluminide. Met. Mater. Int. 12, 467–475 (2006).Google Scholar
Suresh, S.: Fatigue crack deflection and fracture surface contact. Metall. Trans. A 16, 249–260 (1985).Google Scholar
Wiederhorn, S.M.: Brittle fracture and toughening mechanisms in ceramics. Annu. Rev. Mater. Sci. 14, 373–403 (1984).Google Scholar
Rigney, J.D. and Lewandowski, J.J.: Effects of reinforcement size and distribution on fracture toughness of composite nickel aluminide intermetallics. Mater. Sci. Eng., A 158, 31–45 (1992).Google Scholar