The Effect of sintering temperature on microstructure and hardness of milled WC- 20 wt.% equiatomic (Fe,Co) cemented carbides

Document Type: Research Paper


Department of Materials Engineering, Isfahan University of Technology, Isfahan, Iran.


In this study, WC–20 wt.% equiatomic (Fe,Co) powder mixture was milled in a planetary ball mill. The effects of different milling time (15 min, 5h, 10h, and 25 h) and sintering temperatures on the microstructure and mechanical properties of this equi-Fe substituted cermet were investigated. The structural evolution and the crystallite size changes of the powders during milling were monitored by X-ray diffraction (XRD). Microstructure developments of the samples were examined using scanning electron microscope (SEM). The results showed that the crystalline size of WC and internal strain were 22 nm and about 1.1 % after 25 hours of milling, respectively. The hardness and the relative density of the WC-20wt.% (Fe,Co) composites consolidated by conventional sintering at different temperatures, ranging from 1150 to 1450 ˚C in hundreds, were investigated. The optimized sintering temperature was measured at 1350°C. At a constant sintering temperature, 1350°C, the highest relative density of 98.2% and hardness of 1281 (HV30) were obtained for the milling time of 25h.


Main Subjects



[1]        S.A. Hewitt, K.A. Kibble, “Effects of ball milling time on the synthesis and consolidation of nanostructured WC–Co composites”, Int. J. Refract. Met. Hard. Mater., Vol. 27, 2009, pp. 937–48.

[2]        Y. Wang, Z. Xu, “Nanostructured Ni–WC–Co composite coatings Fabricated by electrophoretic deposition”, Surf. Coat. Tech., Vol. 200, 2006, pp. 3896 –902.

[3]        G. Gille, J. Bredthauer., B. Gries, B. Mende, and W. Heinrich, “Advanced and new grades of WC and binder powder-their properties and application”, Int. J. Refract. Met. Hard. Mater., Vol. 18, 2000, pp. 87–102.

[4]        K.P. Plucknet, P.F. Becher and K.B. Alexander, “In situ SEM observation of the fracture behaviour of Titanium Carbide/Nickel Aluminide composites”, J. Microscopy, Vol. 185, 1997, pp. 206-216.

[5]        C. Hanyaloglu, B. Aksakal, J. D. Bolton, “Production and indentation analysis of WC/Fe-Mn as an alternative to cobalt-bonded hardmetals Materials Characterization”, Vol. 47, 2001, pp. 315-322.

[6]        R. González, J. Echeberría, J. M. Sánchez and F. Castro, “WC-(Fe,Ni,C) hardmetals with improved toughness through isothermal heat treatments”, J. Mater. Sci., Vol. 30(13), 1995, pp. 3435-3439.

[7]        J.M. Guilemany, I. Sanchiz, B. G. Mellor, N. Llorca, and J. R. Miguel, “Mechanical-Property Relationships of Co/WC and Co-Ni-Fe/WC Hard Metal Alloys”, Int. J. Refract. Met. Hard. Mater., Vol. 12, 1993, pp. 199-206.

[8]     R. Cooper, S. A. Manktelow, F. Wong, L. E. Collins, “The sintering characteristics and properties of hard metal with Ni–Cr binders”, Mater. Sci. Eng. A, Vol. 105-106, 1988, pp. 269-273.

[9]        T.W. Penrise, “Alternative binders for hard metals”, J. Mater. Shap. Tech., Vol. 5, 1987, pp. 35-9.

[10]      V. A. Tracey, “Nickel in hardmetals”, Int. J. Refract. Met. Hard. Mater., Vol. 11, 1992, pp. 137-149.

[11]      L. Prakash, Proceedings of 12th International Plansee Seminar, Reutte, H. Bildstein, ed., Pion Ltd, London, UK, 1990.

[12]      B. Wittmann, W.D.Schubert, B. Lux, “WC grain growth and grain growth inhibition in nickel and iron binder hardmetals”. Int. J. Refract. Met. Hard. Mater., Vol. 20, 2002, pp. 51–60.

[13]      C.T. Peters and S.M. Brabyn, “Properties of nickel substituted hardmetals and their performance in hard rock drill bits”. Met. Powd. Rep., Vol. 42, 1987, pp. 863–865.

[14]      F.L. Zhang, C.Y. Wang, M. Zhu, “Nanostructured WC/Co copmposite powder prepared by high energy ball milling”, Scripta. Mater., Vol. 49, 2003, pp. 1123-28.

[15]      M. S.El-Eskandarany, A. A. Mahday, H.A. Ahmed, A.H. Amer, “Synthesis and characterizations of ball-milled nanocrstalline WC and nanocomposite WC-Co powders and subsequent consolidations”, J. Alloy. Compd., Vol. 312(1-2), 2000, pp. 315-25.

[16]      Z. Zak Fang, Xu Wang, T. Ryu, K. Sup Hwang, H.Y. Sohn, “Syntesis, sintering, and mechanical properties of nanocrystalline cemented tungsten carbide- A review”, Int. J. Refract. Met. Hard. Mater., Vol. 27, 2009, pp. 288-299.

[17]      G.K. Williamson, W.H. Hall, “X-ray Line Broadening from Filed Aluminium and Wolfram”, Acta. Metall., Vol. 1, 1953, pp. 22-31.

[18]      Y.D. Kim, J.Y. Chung, J.  Kim, H. Jeon, “Formation of nanocrystalline Fe–Co powders produced by mechanical alloying”, Mater. Sci. Eng., Vol A291, 2000, pp. 17-21.

[19]      H. Moumenia, S. Alleg, J.M. Greneche, “Structural properties of Fe50Co50 nanostructured powder prepared by mechanical alloying”, J. Alloy. Compd, Vol. 386, 2005, pp. 12–19.

[20]      C. Suryanarayana, “Mechanical alloying and milling”, Prog. Mater. Sci., Vol.  46, 2001, pp. 1-184.

[21]      Y. Zhong, L. L. Shaw, “Growth mechanisms of WC in WC–5.75 wt% Co”. Ceram. Int., Vol. 37, 2011, pp. 3591–3597.

[22]      Upadhyaya, G. S., “Cemented Tungsten Carbides: Production, Properties and Testing”, Noyes Publication, 1998.

[23]      A.V. Shatov, S.A. Firstov, I.V. Shatova, “The shape of WC crystals in cemented carbides”, Mater. Sci. Eng.A, Vol. 242, 1998, pp. 7–14.

[24]      I.J. Shon, I.K.Jeong., I.Y. Ko, J.M. Doh, K.D. Woo, “Sintering behavior and mechanical properties of WC–10Co, WC–10Ni and WC–10Fe hard materials produced by high-frequency induction heated sintering”, Ceram. Int., Vol. 35, 2009, pp. 339–344.

[25]      S. Kim, S.H. Han, J.K. Park, H.E. Kim, “Variation of WC grain shape with carbon content in the WC–Co alloys during liquid-phase sintering”, Scrip. Mater., Vol. 48,  2003, pp. 635–639.

[26]      S.J.L. Kang, “Sintering: Densification,Grain Growth, and Microstructure”, Elsevier Butterworth-Heinemann Linacre House, Jordan Hill, Oxford OX2 8DP, 2005.

[27]      C.S. Kim, T.R. Massa, G.S. Rohrer, “Modeling the relationship between microstructural features and the strength of WC–Co composites”, Int. J. Refract. Met. Hard. Mater., Vol. 24, 2006, pp.89–100.

[28]      H.C. Lee, J. Gurland, “Hardness and deformation of cemented tungsten carbides”, Mater. Sci. Eng., Vol. 33, 1978, pp. 125-133.

[29]      S. Cha, K. Lee, H. Ryu, S. Hong, “Analytical modeling to calculate the hardness of ultra-fine WC-Co cemented carbides”, Mater. Sci. Eng., Vol. A489, 2008, pp. 234-44.

[30]      M.A. Xueming, J.I. Gang, Z. Ling, D. Yuanda, “Structure and properties of bulk nano-structured WC–CO alloy by mechanical alloying”, J. Alloy. Compd., Vol. 264, 1998, pp. 267–270.

[31]      A.V. Shatov, S.S.Ponomarev, S.A. Firstov, “Modeling the effect of flatter shape of WC crystals on the hardness of WC-Ni cemented carbides”, Int. J. Refract. Met. Hard. Mater., Vol. 27,  2009, pp. 198–212.

[32]      A. Delanoe, S. Lay, “Evolution of the WC grain shape in WC–Co alloys during sintering: Effect of C content”, Int. J. Refract. Met. Hard. Mater., Vol. 27, 2009, pp. 140–148.

[33]      M.H. Enayati, G.R.Aryanpour., A. Ebnonnasir, “Production of nanostructured WC-Co powder by ball milling”, Int. J. Refract. Met. Hard. Mater., Vol. 27, 2009, pp. 159-163.

[34]      F.L. Zhang, M. Zhu and C.Y. Wang, “Parameters optimization in the planetary ball milling of nanostructured tungsten carbide/cobalt powder”, Int. J. Refract. Met. Hard. Mater., Vol. 26, 2008, pp. 329-333.