Advertisement

Performance of powder-injection-molded W-4.9Ni-2.1Fe components

  • Y.S Zu
  • Y.H Chiou
  • S.T Lin
Testing and Evaluation

Abstract

A 93 wt% W heavy alloy was injection molded into standard tensile test specimens and kinetic energy penetrators. Due to the relatively high activation energy of flow (124 kJ/mol), the rheological behavior of the molten feedstock was very susceptible to temperature variation. Using die sets with constant-volume die cavities, the tensile test specimens could be formed within a wide working window, whereas the penetrator could not be molded without defects because of different jetting phenomena during molding. The penetrator could be molded successfully using a die set whose die cavity progressively expanded during molding. The parts thus formed could subsequently be processed into intact components with full density and low carbon contents (<100 ppm). Their mechanical properties were comparable to or better than those of conventionally processed tungsten heavy alloys. Additional penetration test results indicated that powder injection molding was a viable route for processing high-performance tungsten heavy alloys.

Keywords

kinetic energy penetrator mechanical properties powder injection molding rheological behavior tungsten heavy alloy 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    D.J. Jones and P. Munnery, Production of Tungsten Alloy Penetration Radiation Shields,Powder Metall., Vol 10, 1967, p 156–173Google Scholar
  2. 2.
    W.E. Gurwell, A Review of Embrittlement Mechanisms in Tungsten Heavy Alloys,Prog. in Powder Metallurgy, Vol 42, E.A. Carlson and G. Gaines, Ed., Metal Powder Industries Federation, 1986, p 569–590Google Scholar
  3. 3.
    B.C. Muddle, Interphase Boundary Precipitation in Liquid Phase Sintered W-Ni-Fe and W-Ni-Cu Alloys,Metall. Trans. A, Vol 15A, 1984, p 1089–1098Google Scholar
  4. 4.
    D.V. Edmonds and P.N. Jones, Interfacial Embrittlement in Liquid-Phase Sintered Tungsten Heavy Alloys,Metall. Trans. A, Vol 10A, 1979, p 289–295Google Scholar
  5. 5.
    W.D. Schubert, Aspects of Research and Development in Tungsten and Tungsten Alloys,Refract. Met. Hard Mater., Vol 11, 1992, p 151–157CrossRefGoogle Scholar
  6. 6.
    T.W. Penrice, Development in Materials for Use as Kinetic Energy Penetrators,Powder Metallurgy in Defense Technology, Vol 5, Metal Powder Industries Federation, 1980, p 11–21Google Scholar
  7. 7.
    D. Chaiat, Future P/M Materials for Kinetic Energy Penetrators and Shape Charge Liners,Powder Metallurgy in Defense Technology, Vol 7, W.J. Ullrich, Ed., Metal Powder Industries Federation, 1987, p 185–197Google Scholar
  8. 8.
    R.M. German,Powder Injection Molding, Metal Powder Industries Federation, 1990, p 1–16Google Scholar
  9. 9.
    A. Bose, R.J. Dowding, and G.A. Allen, Powder Injection Molding of a 95W-4Ni-lFe Alloy,Powder Injection Molding Symposium—1992, P.H. Booker, J. Gaspervich, and R.M. German, Ed., Metal Powder Industries Federation, 1992, p 261–274Google Scholar
  10. 10.
    A. Bose, H. Zhang, P. Kemp, and R.M. German, Injection Molding of Molybdenum Treated Tungsten Heavy Alloys,Advances in Powder Metallurgy, Vol 3, E.R. Andreotti and P.J. McGeehan, Ed., Metal Powder Industries Federation, 1990, p 401–413Google Scholar
  11. 11.
    T.S. Wei and R.M. German, Injection Molded Tungsten Heavy Alloy,Int. J. Powder Metall., Vol 24, 1988, p 327–335Google Scholar
  12. 12.
    S.T. Lin and R.M. German, Properties of Fully Densified Injection Molded Carbonyl Iron,Metall. Trans. A, Vol 21 A, 1990, p 2531–2538Google Scholar
  13. 13.
    G.C. Sih, Progressively Expanding Molding with Single or Multiple Selection Controlling Volume Configuration and Rate of Injection Material: Metal or Polymer, U.S. Patent 5,505,896,1996Google Scholar
  14. 14.
    S.T. Lin and R.M. German, Extraction Debinding of Injection Molded Parts by Condensed Solvent,Powder Metall. Int., Vol 21, 1989, p 19–24Google Scholar
  15. 15.
    Y.S. Zu and S.T. Lin, “Optimizing the Mechanical Properties of Injection Molded W-4.9%Ni-2.1%Fe in Debinding,” National Taiwan Institute of Technology, Taipei, 1996Google Scholar
  16. 16.
    A. Bose and R.M. German, Sintering Atmosphere Effects on Tensile Properties of Heavy Alloys,Metall. Trans. A, Vol 19A, 1988, p 2467–2476Google Scholar
  17. 17.
    D.J. Williams,Polymer Science and Engineering, Prentice-Hall, 1972, p 340–355Google Scholar
  18. 18.
    Y.H. Chiou, S.J. Liu, and S.T. Lin, Superplastic Behaviour of a Zirconia Powder-Binder Blend,Ceram. Int., Vol 22,1996, p 35–41Google Scholar
  19. 19.
    P.H. Booker, “Paniculate Injection Molding of Selected Metal Alloys and Ceramics,” presented at 1991 Injection Molding International Symposium (Albany), Metal Powder Industries Federation, 15–17 July 1991Google Scholar
  20. 20.
    R.M. German, K.F. Hens, and S.T. Lin, Key Issues in Powder Injection Molding,Bull. Am. Ceram. Soc., Vol 70,1991, p 1294–1302Google Scholar
  21. 21.
    N. Piccirillo and D. Lee, Jetting Phenomena in Powder Injection Molding,Int. J. Powder Metall., Vol 28, 1992, p 13–25Google Scholar
  22. 22.
    Y.H. Chiou, Y.S. Zu, and S.T. Lin, Partition of Tungsten in the Matrix Phase for Liquid Phase Sintered 93% W-4.9%Ni-2.1 %Fe.,Scr. Mater., Vol 34,1996, p 135–140CrossRefGoogle Scholar
  23. 23.
    R.M. German, J.E. Hanafee, and S.L. Digiallonardo, Toughness Variation Test Temperature and Cooling Rate for Liquid Phase Sintered W-3.5Ni-l.5Fe,Metall. Trans. A, Vol 15A, 1984, p 121–128Google Scholar
  24. 24.
    R.M. German and L.L. Bourguignon, Analysis of High Tungsten Content Heavy Alloys,Powder Metallurgy in Defense Technology, Vol 6, C.L. Freeby and W.J. Ullrich, Ed., Metal Powder Industries Federation, 1985,p 117–131Google Scholar
  25. 25.
    J.M. Sakai and C. Grabarek, Ballistic Tests on Heat Treated Tungsten Alloy Penetrator after Swaging,Powder Metallurgy in Defense Technology, Vol 4, Metal Powder Industries Federation, 1978, p 85–90Google Scholar
  26. 26.
    L.L. Bourguignon and R.M. German, Sintering Temperature Effects on Tungsten Heavy Alloys,Int. J. Powder Metall., Vol 24, 1988,p 115–121Google Scholar
  27. 27.
    J.B. Posthill, M.C. Hogwood, and D.V. Edmonds, Precipitation at Tungsten/Tungsten Interfaces in Tungsten-Nickel-Iron Heavy Alloys,Powder Metall., Vol 29, 1986, p 45–51Google Scholar

Copyright information

© ASM International 1996

Authors and Affiliations

  • Y.S Zu
    • 1
  • Y.H Chiou
    • 1
  • S.T Lin
    • 1
  1. 1.Mechanical Engineering DepartmentNational Taiwan Institute of TechnologyTaipeiRepublic of China

Personalised recommendations