J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (11): 2435-2446.DOI: 10.1016/j.jmst.2019.07.016

• Orginal Article • Previous Articles     Next Articles

Grain size effect on wear resistance of WC-Co cemented carbides under different tribological conditions

Haibin Wangab*(), Mark Geeb, Qingfan Qiua, Hannah Zhangb, Xuemei Liua, Hongbo Niec, Xiaoyan Songa*(), Zuoren Niea   

  1. aCollege of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Education Ministry of China, Beijing University of Technology, Beijing 100124, China
    bNational Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
    cXiamen Tungsten Co., Ltd., Xiamen 361009, China
  • Received:2019-05-15 Revised:2019-06-10 Accepted:2019-06-11 Online:2019-11-05 Published:2019-10-21
  • Contact: Wang Haibin,Song Xiaoyan

Abstract:

The grain-size dependence of wear resistance of WC-Co cemented carbides (with mean WC grain sizes of 2.2 μm, 1.6 μm, 0.8 μm and 0.4 μm, respectively) was investigated under different tribological conditions. The results showed that the grain size had opposite effects on wear resistance of the cemented carbides in dry sliding wear and microabrasion tests. In the former condition, with decrease of WC grain size hence the increase of hardness, plastic deformation, fracture, fragmentation and oxidation were all mitigated, leading to a drastic decrease in the wear rate. In the latter condition, pull-out of WC grains after Co removal dominated the wear, so that the hardness of cemented carbide was not a core factor. As a result, the wear resistance of the cemented carbide generally showed a decreasing trend with decrease of the grain size, except for a slight increase in the ultrafine-grained cemented carbide. Single-pass scratching of the cemented carbides under various loads indicated the same failure mechanism as that in the sliding wear tests. Furthermore, the reasons for severe surface oxidation of the coarse-grained cemented carbides were disclosed.

Key words: Cemented carbide, Grain size, Fracture, Surface oxidation, Grain pull-out, Wear resistance