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Metallurgical and Materials Transactions A

, Volume 32, Issue 11, pp 2885–2893 | Cite as

Densification and structural change of mechanically alloyed W-Cu composites

  • Laszlo J. Kecskes
  • Bradley R. Klotz
  • Kyu C. Cho
  • Robert J. Dowding
  • Matthew D. Trexler
Article

Abstract

Fine-grained, high-density (97+ pct of theoretical density (TD)), 80W-20Cu wt pct (58W-42Cu at. pct) composites have been prepared using nonconventional alloying techniques. The W and Cu precursor powders were combined by a high-energy ball-milling procedure in air or hexane. The mechanically alloyed W+Cu powder mixtures were then cold pressed into green compacts and sintered at 1523 K. The milling medium and milling time were varied to increase product densities with a concomitant order-of-magnitude decrease in grain size. For densification, air was found to be a more effective medium than hexane. From microhardness measurements, it was concluded that the W-Cu alloys were dispersion and solution hardened, but were sensitive to entrapped residual impurities. X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and scanning electron micros-copy (SEM) analyses were used to demonstrate that the as-milled and sintered W-Cu alloy structures were metastable, decomposing into the starting W and Cu components upon heating at or above 723 K.

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References

  1. 1.
    A. Bose and R.M. German: Sintering Theory and Practice, John Wiley & Sons, Inc., New York, NY, 1996.Google Scholar
  2. 2.
    R.M. German, K.F. Hens, J.L. Johnson, and Y. Bin: Advances in Powder Metallurgy and Particulate Materials. Specialty Materials and Composites. Proc. 1993 Int. Conf. on Powder Metallurgy and Particulate Materials, MPIF Press, Princeton, NJ, 1993, pp. 189–202.Google Scholar
  3. 3.
    J. Boscary, S. Suzuki, K. Nakamura, T. Suzuki, and M. Akiba: Fusion Engineering and Design. Proc. 1997 4th Int. Symp. on Fusion Nuclear Technology, Elsevier, Lausanne, Switzerland, 1999, vols. 39–40, Part A, pp. 537–42.Google Scholar
  4. 4.
    Binary Alloy Phase Diagrams, 2d ed., T.B. Massalski, H. Okamoto, PR. Subramanian, and L. Kacprzak, eds., William W. Scott Publishers, New York, NY, 1990, pp. 1503–04.Google Scholar
  5. 5.
    G.G. Lee, G.H. Ha, D.W. Lee, B.K. Kim, and I.S. Ahn: TMS Annual Meeting Chemistry and Physics of Nanostructures and Related Non-Equilibrium Materials. Proc. 1997 TMS Annual Meeting, TMS, War-rendale, PA, 1997, pp. 163–70.Google Scholar
  6. 6.
    H.J. Ryu, S.H. Hong, J.W. Noh, and W.H. Baek: 2nd Int. Symp. on Advanced PM Processing (ISAPM-2), Pohang, Korea, 1996, pp. 196–203.Google Scholar
  7. 7.
    M.L. Ovecoglu, B. Ozkal, and C. Suryanarayana: J. Mater. Res., 1996, vol. 11 (7), pp. 1673–82.CrossRefGoogle Scholar
  8. 8.
    J.C. Kim and I.H. Moon: Nanostr. Mater., 1998, vol. 10 (2), pp. 283–90.CrossRefGoogle Scholar
  9. 9.
    A. Upadhyaya and R.M. German: Int. J. Powder Metall, 1998, vol. 34 (2), pp. 43–55.Google Scholar
  10. 10.
    B.D. Cullity: Elements of X-ray Diffraction, 2nd ed., Addison-Wesley Publishing Company, Inc., Reading, MA, 1978, pp. 359–360.Google Scholar
  11. 11.
    E. Gaffet, C. Louison, M. Harmelin, and F. Faudot: Mater. Sci. Eng., 1991, vol. A134, pp. 1380–84.Google Scholar
  12. 12.
    J. Cornejo, V. Martinez, and S. Ordonez: Key Engineering Materials, 2nd Int. Latin-American Conf. on Powder Technology, Foz do Iguacu, Brazil, 2001, vols. 189–191, pp. 561–66.Google Scholar
  13. 13.
    D.R. Askeland: The Science and Engineering of Materials, 2nd ed., PWS-Kent Publishing Company, Boston, MA, 1989, p. 686.Google Scholar

Copyright information

© ASM International & TMS–The Minerals, Metals and Materials Society 2001

Authors and Affiliations

  • Laszlo J. Kecskes
    • 1
  • Bradley R. Klotz
    • 1
  • Kyu C. Cho
    • 1
  • Robert J. Dowding
    • 1
  • Matthew D. Trexler
    • 2
  1. 1.the Weapons and Materials Research DirectorateUnited States Army Research LaboratoryAberdeen Proving Ground
  2. 2.the Materials Science and Engineering DepartmentGeorgia Institute of TechnologyAtlantaGeorgia

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