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Non-equilibrium Microstructure and Thermal Stability of Plasma-sprayed Al–Si Coatings

Published online by Cambridge University Press:  01 August 2005

K.H. Baik*
Affiliation:
Department of Metallurgical Engineering, Chungnam National University, Yuseong, Daejeon 305-764, Korea
H.K. Seok
Affiliation:
Division of Materials Science and Technology, Korea Institute of Science and Technology, Seoul 136-791, Korea
H.S. Kim
Affiliation:
Department of Metallurgical Engineering, Chungnam National University, Yuseong, Daejeon 305-764, Korea
P.S. Grant
Affiliation:
Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

A splat-quenched, thick Al–Si deposit was manufactured by low-pressure plasma spraying (LPPS) and investigated in terms of microstructural inhomogeneity, Si solid solubility in α–Al, formation of metastable phases, and thermal stability. The LPPS Al–Si deposit had an inhomogeneous, layered microstructure consisting of splat-quenched lamellae and the incorporation of unmelted or partially melted particles. The splat-quenched Al–Si lamellae were formed by deposition of a fully liquid droplet and had an almost featureless microstructure at relatively low magnifications. There was a significant reduction in the α–Al lattice parameter in the LPPS Al–Si deposit because of extended Si solubility in the α–Al matrix. Transmission electron microscopy investigations showed that the splat quenching of liquid Al–Si droplet led to (i) columnar grain growth of α–Al(Si), (ii) formation of nano-sized Si precipitates in the Al matrix which was supersaturated with Si; and (iii) formation of amorphous Si phase embedded in the crystalline Al matrix. On reheating, the amorphous Si transformed into fine crystalline Si by interdiffusion of Al and Si atoms. Simultaneously, Si precipitation occurred in the supersaturated α–Al matrix. The overall activation energy for the Si crystallization/precipitation was estimated as ∼81 kJ/mol from a modified Kissinger analysis.

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Articles
Copyright
Copyright © Materials Research Society 2005

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References

REFERENCES

1Inoue, A.: Amorphous, nanoquasicrystalline and nanocrystalline alloys in Al-based systems. Prog. Mater. Sci. 43, 365 (1998).CrossRefGoogle Scholar
2Guo, J.Q. and Ohters, K.: Microstructures and mechanical properties of rapidly solidified high strength Al–Ni based alloys. Acta Mater. 46, 3829 (1998).CrossRefGoogle Scholar
3Li, P.Y., Yu, H.J., Chai, S.C. and Li, Y.R.: Microstructure and properties of rapidly solidified powder metallurgy Al–Fe–Mo–Si alloys. Scripta Mater. 49, 819 (2003).CrossRefGoogle Scholar
4El-Eskandarany, M.S., Saida, J. and Inoue, A.: Amorphization and crystallization behaviors of glassy Zr70Pd30 alloys prepared by different techniques. Acta Mater. 50, 2725 (2002).CrossRefGoogle Scholar
5Honda, K., Hirose, A. and Kobayashi, K.F.: Properties of titanium-aluminide layer formed by low pressure plasma spraying. Mater. Sci. Eng., A 222, 212 (1997).CrossRefGoogle Scholar
6Hedges, M.K., Newbery, A.P. and Grant, P.S.: Characterization of electric arc spray formed Ni superalloy IN718. Mater. Sci. Eng., A 326, 79 (2002).CrossRefGoogle Scholar
7Baik, K.H.: Processing and properties of metallic and ceramic-matrix composites by a novel spraying technique. Met. Mater. Int. 10, 133 (2004).CrossRefGoogle Scholar
8Baik, K.H., Grant, P.S. and Cantor, B.: The equiaxed-banded microstructural transition during low pressure plasma spraying. Acta Mater. 52, 199 (2004).CrossRefGoogle Scholar
9Cantor, B., Baik, K.H. and Grant, P.S.: Development of microstructure in spray formed alloys. Prog. Mater. Sci. 42, 373 (1997).CrossRefGoogle Scholar
10Grosdidier, T., Tidu, A. and Liao, H.L.: Nanocrystalline Fe–40Al coating processed by thermal spraying of milled powder. Scripta Mater. 44, 387 (2001).CrossRefGoogle Scholar
11Jin, H.W., Rhyim, Y.M., Hong, S.G. and Park, C.G.: Microstructural evolution of the rapidly quenched Fe–Cr–B alloy thermal spray coatings. Mater. Sci. Eng., A 304–306, 1069 (2001).CrossRefGoogle Scholar
12Tomida, S., Nakata, K., Shibata, S., Zenkouji, I. and Saji, S.: Improvement in wear resistance of hyper-eutectic Al–Si cast alloy by laser surface remelting. Surf. Coat. Technol. 169–170, 468 (2003).CrossRefGoogle Scholar
13Murakami, K., Takuno, N., Okamoto, T. and Miyamoto, Y.: Temperature rise of rapidly solidified deposit layers of Al–Si alloys during low pressure plasma spraying and its effect on their structures and mechanical properties. Mater. Sci. Eng., A 154, 93 (1992).CrossRefGoogle Scholar
14Kuroda, S., Kawakita, J., and Takemoto, M.: Marine exposure tests of thermal sprayed coatings in Japan, in Proceeding of International Thermal Spray Conference—2003, edited by Moreau, C. and Marple, B. (ASM International, Materials Park, OH, 2003), p. 343.Google Scholar
15Baik, K.H. and Grant, P.S. Optimization of vacuum plasma spraying for composite production, in Materials, Functionality & Design, Vol. 1 (Metals and Composites), edited by Sarton, L.A.J.I. and Zeedijk, H.B., (Netherlands Society for Materials Science, The Netherlands, 1997), p. 341.Google Scholar
16Baik, K.H. and Grant, P.S.: Microstructural evaluation of monolithic and continuous fibre reinforced Al–12 wt% Si produced by low pressure plasma spraying. Mater. Sci. Eng., A 265, 77 (1999).CrossRefGoogle Scholar
17Cullity, B.D.: Elements of X-ray Diffraction, 2nd ed. (Addison-Wesley, Reading, MA, 1977).Google Scholar
18Branes, E.A. and Brook, G.B.: Smithells Metals Reference Book, 7th ed. (Butterworth-Heinemann, Oxford, U.K., 1992).Google Scholar
19Matusita, K. and Sakka, S.: Kinetic study of crystallization of glass by differential thermal analysis—Criterion on application of Kissinger plot. J. Non-Cryst. Solids 38–39, 741 (1980).CrossRefGoogle Scholar
20Pratap, A., Raval, K.G. and Awasthi, A.M.: Kinetics of crystallization of ternary titanium based amorphous alloy. Mater. Sci. Eng., A 304–306, 357 (2001).CrossRefGoogle Scholar
21Konno, T.J. and Sinclair, R.: Crystallization of silicon in aluminium/amorphous-silicon multilayers. Philos. Mag. B 66, 749 (1992).CrossRefGoogle Scholar
22Antonione, C., Battezzati, L. and Marino, F.: Structure and stability of rapidly solidified Al–Si based alloys. Mater. Sci. Lett. 5, 586 (1986).CrossRefGoogle Scholar
23Bendijk, A., Delhez, R., Katgerman, L., De Keijser, Th.H., Mittemeijer, E.J. and Van Der Pers, N.M.: Characterization of Al–Si alloys rapidly quenched from the melt. J. Mater. Sci. 15, 2803 (1980).CrossRefGoogle Scholar
24Birol, Y.: Microstructural characterization of a rapidly-solidified Al–12 wt% Si alloy. J. Mater. Sci. 31, 2139 (1996).CrossRefGoogle Scholar
25Niu, F. Functional nanocomposite thin films by co-sputtering, D.Phil. Thesis, University of Oxford, U.K. (1998).Google Scholar