Numerical Heat Transfer Modelling in Spray Formed IN718 Billets


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A numerical finite difference model has been developed to describe the transient heat flow inside Ni superalloy IN718 billets manufactured by spray forming. This model described the progressive build-up and solidification of the billets, and accounted for the latent heat of solidification, convective and radiation heat loss, and heat removal through the substrate, coupled with transient heat transfer in the substrate. The model has been used to predict critical values of important process parameters: average droplet arrival temperature, deposition rate, and billet surface convective heat transfer coefficient, in terms of key microstructural features by correlation of quantitative predictions with qualitative microstructural investigations of the as-sprayed billets. On a micro scale, repeated re-heating/remelting of deposited layers because of subsequent deposition was predicted and has been suggested to be beneficial in reducing porosity and microsegregation, as well as in playing an important role in the formation of the characteristic equiaxed spray formed microstructure.



Materials Science Forum (Volumes 475-479)

Main Theme:

Edited by:

Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie




Z. Shi et al., "Numerical Heat Transfer Modelling in Spray Formed IN718 Billets", Materials Science Forum, Vols. 475-479, pp. 2803-2806, 2005

Online since:

January 2005




[1] P.S. Grant, Prog. Mater. Sci. 39 (1995), 497.

[2] P. Mathur, D. Apelian and A. Lawley, Acta Metall. 37(2) (1989), 429.

[3] B.P. Bewlay and B. Cantor, J. Mater. Res. 6 (1991), 1433.

[4] P.S. Grant, P.P. Maher and B. Cantor, Mater. Sci. Engng A179/A180 (1994), 72.

[5] B. Cantor, K.H. Baik, and P.S. Grant, Prog. Mater. Sci. 42 (1997), 373.

[6] N.H. Pryds, J.H. Hattel, T.B. Pedersen and J. Thorborg, Acta Materialia 50 (2002), 4075.

[7] O. Meyer, U. Fritsching and K. Bauckhage, Int. J. Therm. Sci. 42 (2003), 153.

[8] D. Bergmann and U. Fritsching, Int. J. Therm. Sci. 43 (2004), 403.

[9] P.N. Quested, K.C. Mills, R.F. Brooks, A.P. Day, R. Taylor and H. Szelagowski, in A. Mitchell and P. Auburtin (eds): Proc. of the 1997 Int. Symp. on Liquid Metal Processing and Casting, New Mexico, Feb. 16-19, 1997, American Vacuum Society, pp.1-17.

[10] MatWeb. com, The Online Materials Database, Cordierite.

[11] O. Meyer, A. Schneider, V. Uhlenwinkel and U. Fritsching, Int. J. Therm. Sci. 42 (2003), 561.

[12] A.G. Leatham, H.S. Coombs, J.B. Forrest, A.J.W. Ogilvy, R. Ross and L.G. Elias, US patent No. US6312535B1, Mar. (2000).

[13] W.T. Carter Jr. and R.M.F. Jones, Adv. Mater. Process. 160(7) (2002 ), 27-29.

[14] K.H. Baik, P.S. Grant and B. Cantor, Acta Mater. 52 (2004), 199. Fig. 5 Effect of convection heat transfer coefficient on the final solidification time. Fig. 6 Temperature evolution for the centre and the peripheral points of two adjacent layers.