Effect of Particle Size and Vacuum Sintering Temperature on Phase Composition and Mechanical Properties of WC-12 wt% Co Hardmetals

Abstract:

The experimental results indicated that the WC-12wt% Co specimens showed excellent mechanical properties and microstructure by the optimal sintering process. The G5 specimen sintered at 1400°C/1 h achieved a relative density of 98% and a hardness of HRA 88.5. Meanwhile, the TRS increased to 2400 MPa. F12 specimens that sintered at 1350°C/1 h achieved a relative density of 99% and a hardness of HRA 92.5. The TRS was also enhanced to 2170 MPa. In this study, the η phase (Co3W3C) precipitated at a high sintering temperature. The precipitations generated by liquid phase sintering gathered in some specific regions of the specimens and reacted with the WC particles. In addition, Co3W3C was a hard and brittle phase that resulted in a low TRS for the specimens; and a large amount of η phases were detrimental to the fracture toughness of the specimens.

• Periodical: Key Engineering Materials (Volumes 531-532)
• Pages: 3-7
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.531-532.3
• Online since: December 2012
• Authors: Shih Hsien Chang, Chung Wei Lee, Kuo Tsung Huang, Ming Wei Wu
• Keywords: Hardness, Sintering, TRS Phase, WC-12wt% Co, η-Phase

References

[1] C.H. Allibert: Int. J. Refract. Met. Hard Mat. 19 (2001) 53-61.

[2] D. Mari and D.R. Gonseth: Wear. 165 (1993) 9-17.

[3] Y.V. Milman, S. Luyckx and I.T. Northrop: Int. J. Refract. Met. Hard Mat. 17 (1999) 39-44.

[4] S.H. Chang, S.C. Lee, C.H. Tam, K.T. Huang, C. Liang and F.C. Tai: Powder Metall. 54 (2011) 325-330.

[5] A. Saidi and M. Barati: J. Mater. Process. Technol. 124 (2002) 166-170.

[6] S.H. Chang, T.P. Tang, K.T. Huang and F.C. Tai: Powder Metall. 54 (2011) 507-512.

[7] H.C. Kim, D.Y. Oh and I.J. Shon: Int. J. Refract. Met. Hard Mat. 22 (2004) 197-203.

[8] A.S. Kurlov and A.A. Remple: Inorg Mater. 43 (2007) 602-607.

[9] S.H. Chang, S.C. Lee, T.P. Tang and H.H. Ho: Mater. Trans. 47 (2006) 426-432.