Abstract
Carbon contamination from the thermoplastic binder is an inherent problem with the metal powder injection molding process. Residual carbon in the compacts after debinding has a strong impact on the sintering process, microstructure, and mechanical properties. In this study, injection molded 17-4 PH stainless steel was debound to two levels of residual carbon, 0.203 ± 0.014 wt% and 0.113 ± 0.008 wt%, by elevating the debinding temperature from 450°C to 600°C. Dilatometry in H2 atmosphere shows that the 600°C-debound compacts shrink much faster than those debound at 450°C when the sintering temperature rises to over 1200°C. Density measurements for tensile bars sintered between 1260°C and 1380°C confirm the beneficial effect of low residual carbon content on sintering shrinkage. Quantitative metallography reveals that more δ-ferrite forms along austenite grain boundaries during sintering of the 600°C-debound compacts. In both samples, density gradients across the compact section are correlated with the residual carbon content and corresponding δ-ferrite formation. Finally, tensile tests show that the 600°C-debound compacts have lower tensile strength but higher ductility than those debound at 450°C. The relevant mechanisms are discussed with a focus on the effects of residual carbon content, δ-ferrite amount, and porosity.
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References
R. M. German and D. Kubish, Int.J.Powder Metall. 29 (1993) 47.
R. M. German and A. Bose, in “Injection Molding of Metals and Ceramics” (Metal Powder Industries Federation, Princeton, New Jersey, 1997) p. 11.
M. A. Phillips, E. L. Streicher, M. Renowden, R. M. German and J. M. Friedt, in Proceedings of the 1992 Powder Injection Molding Symposium, San Francisco, June 1992, edited by P. H. Booker, J. Gaspervich and R. M. German (Metal Powder Industries Federation, Princeton, New Jersey, 1992) p. 371.
H. Ohtsubo, K. Maruta, K. Nishimura and Y. Makiishi, in Proceedings of the 1992 Powder Injection Molding Symposium, San Francisco, June 1992, edited by P. H. Booker, J. Gaspervich and R. M. German (Metal Powder Industries Federation, Princeton, New Jersey, 1992) p. 409.
J. W. Newkirk, J. A. Sago and G. M. Brasel, in “Processing and Fabrication of Advanced Materials, ” Vol. VII (The Minerals, Metals and Materials Society, Warrendale, PA, 1998) p. 213.
J. R. Davis, in “Stainless Steels” (ASM International, Materials Park, Ohio, 1994) p. 13.
R. T. Fox, D. Lee, M. K. Bulger and R. M. German, in “Advances in Powder Metallurgy, ” Vol. 3 (Metal Powder Industries Federation, Princeton, New Jersey, 1990) p. 359.
H. Zhang and R. M. German, in Proceedings of the 1992 Powder Injection Molding Symposium, San Francisco, June 1992, edited by P. H. Booker, J. Gaspervich and R. M. German (Metal Powder Industries Federation, Princeton, New Jersey, 1992) p. 219.
S. Banerjee, in Proceedings of the 1992 Powder Injection Molding Symposium, San Francisco, June 1992, edited by P. H. Booker, J. Gaspervich and R. M. German (Metal Powder Industries Federation, Princeton, New Jersey, 1992) p. 181.
J. J. Valencia, T. J. McCABE and H. Dong, in “Advances in Powder Metallurgy and Particulate Materials, ” Vol. 2 (Metal Powder Industries Federation, Princeton, New Jersey, 1995) p. 6.
J. J. Valencia and J. R. Spirko, in “Advanced Particulate Materials and Processes” (Metal Powder Industries Federation, Princeton, New Jersey, 1997) p. 411.
T. Baba, H. Miura, T. Honda and Y. Tokuyama, in “Advances in Powder Metallurgy and Particulate Materials, ” Vol. 2 (Metal Powder Industries Federation, Princeton, New Jersey, 1995) p. 6.
H. Kyogoku, S. Komatsu, H. Nakayama, H. Jinushi and K. Shinohara, in “Advances in Powder Metallurgy and Particulate Materials, ” Vol. 3 (Metal Powder Industries Federation, Princeton, New Jersey, 1997) p. 18.
K. A. Green, in “Advances in Powder Metallurgy and Particulate Materials, ” Vol. 2 (Metal Powder Industries Federation, Princeton, New Jersey, 1998) p. 5.
J. C. Lasalle and M. Zedalis, JOM-J MIN MET MAT S 51 (1999) 38.
Y. Wu, D. Blaine, B. Marx, C Schlaefer and R. M. German, Metall.Mater.Trans. 33A , in press.
R. M. German, in “Sintering Theory and Practice” (Wiley, New York, 1996) p. 68.
I. Kaur, W. Gust and L. Kozma, in “Handbook of Grain and Interphase Boundary Diffusion Data” (Ziegler Press, Stuttgart, 1989) p. 536.
M. Kamada and Y. Tokunaga, J.Jpn.I.Met. 55 (1991) 887.
T. M. Puscas, A. Molinari, J. Kazior, T. Pieczonka and M. Nykiel, Powder Metall. 44 (2001) 48.
P. Datta and G. S. Upadhyaya, Mater.Chem.Phys. 67 (2001) 234.
A. Bag and K. K. Ray, Metall.Mater.Trans. 32A (2001) 2400.
R. M. German, in “Powder Metallurgy Science” (Metal Powder Industries Federation, Princeton, New Jersey, 1994) p. 383.
J. M. Holt, H. Mindlin and C. Y. Ho, in “Structural Alloys Handbook, ” Vol. 2 (CINDAS/Purdue University, West Lafayette, Indiana, 1996) p. 6.
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Wu, Y., German, R.M., Blaine, D. et al. Effects of residual carbon content on sintering shrinkage, microstructure and mechanical properties of injection molded 17-4 PH stainless steel. Journal of Materials Science 37, 3573–3583 (2002). https://doi.org/10.1023/A:1016532418920
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DOI: https://doi.org/10.1023/A:1016532418920