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Journal of Central South University of Technology

, Volume 13, Issue 6, pp 603–607 | Cite as

Phase transformation of nano-grained W(Co, C) composite powder and its phase constitute

  • Cao Shun-hua  (曹顺华)Email author
  • Cai Zhi-yong  (蔡志勇)
  • Zhou Jian-hua  (周建华)
  • Li Jiong-yi  (李炯义)
  • Lin Xin-ping  (林信平)
Article

Abstract

A new process of WC-Co cemented carbide was developed by using nano-grained W(Co, C) composite powders as raw materials processed by high-energy ball milling. X-ray diffraction(XRD), differential thermal analysis (DTA), thermo-gravimetric (TG) analysis and coercive forces of the sintered samples were adopted to analyze the phase transformation and constitution, and the microstructures of sintered samples were characterized by scanning electron microscopy(SEM). The results show that the as-milled powders are transformed into transitional phases W2C and η (Co3W3C or Co6W6C) during sintering, and finally transformed into WC and Co phases completely at 1 250 °C for 30 min, and a large number of fibrous WC grains with about 1.2 μm in length and 100 nm in radial dimension are formed in the sintered body at 1 300 °C.

Key words

cemented carbide phase transformation high-energy ball milling fibrous WC grain 

CLC number

TG135.5 

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References

  1. [1]
    Yao Z G, Stiglich J J, Sudarshan T S. Nanosized WC-10Co holds promise for the future[J]. Metal Powder Report, 1998, 53(3): 26–33.CrossRefGoogle Scholar
  2. [2]
    Yao Z G, Stiglich J J, Sudarshan T S. WC-Co enjoys proud history and bright future[J]. Metal Powder Report, 1998, 53(2): 32–36.CrossRefGoogle Scholar
  3. [3]
    Kear B H, Strutt P R. Chemical pressing and applications for nanostructured materials[J]. Nanostructured Materials, 1995, 6(1–4): 227–236.CrossRefGoogle Scholar
  4. [4]
    Sadangi R K, McCandlish L E, Kear B H, et al. Grain growth inhibition in liquid phase sintered WC/Co powder[J]. International Journal of Powder Metallurgy, 1999, 35(1): 27–33.Google Scholar
  5. [5]
    Mohan K, Strutt P R. Microstructure of spray converted nanostructured tungsten carbide-cobalt composite[J].Materials Science and Engineering A, 1996, A209(1/2): 237–242.CrossRefGoogle Scholar
  6. [6]
    El-Eskandarany M S, Mahday A A, Ahmed H A, et al. Synthesis and characterizations of ball milled nanocrystalline WC and nanocomposite WC-Co powders and subsequent consolidations[J]. Journal of Alloys and Compounds, 2000, 312(3): 315–325.CrossRefGoogle Scholar
  7. [7]
    Zhong Y Z, Wahlberg S, Ming S W, et al. Processing of nanostructured WC-Co powder from precursor obtained by co-precipitation[J].Nanostructured Materials, 1999,12(1): 163–166.CrossRefGoogle Scholar
  8. [8]
    Gille G, Szesny B, Dreyer K, et al. Submicron and ultrafine grained hardmetals for microdrills and metal cutting inserts[J]. International Journal of Refractory Metals & Hard Materials, 2002, 20(1): 3–22.CrossRefGoogle Scholar
  9. [9]
    Schubert W D, Bock A, Lux B. General aspects and limits of conventional ultrafine WC powder manufacture and hard metal production[J]. International Journal of Refractory Metals & Hard Materials, 1995, 13(5): 281.CrossRefGoogle Scholar
  10. [10]
    CAO Shun-hua, CAO Hai-yan, LI Yuan-yuan et al. Synthesis of nano-grained WC-10Co composite powders by reaction thermal treatment technique[J]. Journal of Center South University of Technology, 2003, 34(5): 480–483.(in Chinese)Google Scholar
  11. [11]
    Gilman P S, Benjamin J S. Mechanical alloying[J]. Ann Rer Meter Sci, 1983, 13: 279–300.CrossRefGoogle Scholar
  12. [12]
    da Costa F A, da Silva A G P, Umbelino G U. The influence of the dispersion technique on the characteristics of the W-Cu powders and on the sintering behavior[J]. Powder Technology, 2003, 134(1/2): 123–132.CrossRefGoogle Scholar
  13. [13]
    Lavergne O, Robaut F, Hodaj F, et al. Mechanism of solid-state dissolution of WC in Co-based solutions[J]. Acta Materalia, 2002, 50(7): 1683–1692.CrossRefGoogle Scholar
  14. [14]
    Cho K H, Lee J W, Chung I S. A study on the formation of anomalous large WC grain and eta phase[J]. Materials Sciences and Engineering A, 1996, A209(1/2): 298–301.CrossRefGoogle Scholar
  15. [15]
    Liu S R, Song J T, He J M, et al. Phase transformation of WC-Co alloy[J]. Cemented Carbide, 2001, 18(3): 129–133.(in Chinese).Google Scholar
  16. [16]
    Sundin S, Haglund S. A comparison between magnetic properties and grain size for WC/Co hard materials containing additives of Cr and V[J]. International Journal of Refractory & Hard Materials, 2000, 18(6): 297–300.CrossRefGoogle Scholar

Copyright information

© Published by: Central South University Press, Sole distributor outside Mainland China: Springer 2006

Authors and Affiliations

  • Cao Shun-hua  (曹顺华)
    • 1
    Email author
  • Cai Zhi-yong  (蔡志勇)
    • 1
  • Zhou Jian-hua  (周建华)
    • 1
  • Li Jiong-yi  (李炯义)
    • 1
  • Lin Xin-ping  (林信平)
    • 1
  1. 1.State Key Laboratory of Powder MetallurgyCentral South UniversityChangshaChina

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