Interparticle Liquid Film Formation during Spark Plasma Sintering of Inconel 718 Superalloy

Abstract:

The use of powder metallurgy for near net shape sintering of superalloy could lead to major savings in machining time and material. The main challenge in sintering Inconel 718 is to avoid the formation of a prior particle boundary (PPB) network that is deleterious to the mechanical properties. Using the Spark Plasma Sintering (SPS) technique, it is believed that Inconel 718 powders could be sintered without forming a PPB network due to the fast heating rate achieved and the reported cleaning effect of particle surfaces by the interparticle arc discharges. In this study, Inconel 718 was consolidated to near-full density at 1200°C under 50 MPa of pressure with heating rates ranging from 20°C/min to 800°C/min. The densification behavior of the powder was studied through the analysis of the densification curves and observation of the microstructure evolution from interrupted tests. The fast densification of Inconel 718 in SPS was linked to the formation of a supersolidus liquid phase due to the nature of the heating in this technique.

• Periodical: Advanced Materials Research (Volume 409)
• Pages: 763-768
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.409.763
• Online since: November 2011
• Authors: David Levasseur, Mathieu Brochu
• Keywords: Liquid Phase Sintering (LPS), Spark Plasma Sintering (SPS), Superalloy

References

[1] Paulonis, D.F., J.M. Oblak, and D.S. Duvall, Precipitation in Nickel-Base Alloy 718. Asm Transactions Quarterly, 1969. 62(3): p.611.

[2] Reed, R.C., The superalloys : fundamentals and applications. 2006, Cambridge, UK; New York: Cambridge University Press.

[3] Menzies, R.G., R.H. Bricknell, and A.J. Craven, Stem Microanalysis Of Precipitates And Their Nuclei In A Nickel-Base Super-Alloy. Philosophical Magazine A, 1980. 41(4): pp.493-508.

DOI: 10.1080/01418618008239328

[4] Billard, D. and J.P. Trottier, Hydrogen Chloride Surface Pretreatment of Nickel Superalloy Powders. Powder Metallurgy International, 1978. 10: p. p.83.

[5] Risbud, S.H., J.R. Groza, and M.J. Kim, Clean Grain-Boundaries in Aluminum Nitride Ceramics Densified Without Additives by a Plasma-Activated Sintering Process. Philosophical Magazine B, 1994. 69(3): pp.525-533.

DOI: 10.1080/01418639408240126

[6] Mizuguchi, T., S.Q. Guo, and Y. Kagawa, Transmission electron microscopy characterization of spark plasma sintered ZrB2 ceramic. Ceramics International, 2010. 36(3): pp.943-946.

DOI: 10.1016/j.ceramint.2009.10.025

[7] NAGAE, et al., Effects of pulse current on an aluminum powder oxide layer during pulse current pressure sintering. Vol. 43. 2002, Sendai, JAPON: Japan Institute of Metals.

DOI: 10.2320/matertrans.43.1390

[8] Tokita, M. Mechanism of Spark Plasma Sintering. in Proceeding of the 2000 Powder Metallurgy World Congress. 2000. Kyoto, Japan.

[9] Frei, J.M., U. Anselmi-Tamburini, and Z.A. Munir, Current effects on neck growth in the sintering of copper spheres to copper plates by the pulsed electric current method. Journal of Applied Physics, 2007. 101(11).

DOI: 10.1063/1.2743885

[10] Song, X., X. Liu, and J. Zhang, - Neck Formation and Self-Adjusting Mechanism of Neck Growth of Conducting Powders in Spark Plasma Sintering. 2006. - 89(- 2): p. - 500.

DOI: 10.1111/j.1551-2916.2005.00777.x

[11] Knorovsky, G., et al., INCONEL 718: A solidification diagram. Metallurgical and Materials Transactions A, 1989. 20(10): pp.2149-2158.

DOI: 10.1007/bf02650300

[12] Munir, Z.A., D.V. Quach, and M. Ohyanagi, Electric Current Activation of Sintering: A Review of the Pulsed Electric Current Sintering Process. Journal of the American Ceramic Society, 2011. 94(1): pp.1-19.

DOI: 10.1111/j.1551-2916.2010.04210.x