Abstract
Indentation hardness of cemented carbides has been studied on the basis of Tabor’s theory. The surfaces of the specimens with 5∼25 wt% cobalt were finished by diamond paste-lapping after grinding with 150 mesh and 1500 mesh resin-bonded diamond wheels. Then, indentations were made by Rockwell cone, the Vickers cone and the ball indenter.
The results obtained are as follows:
(1) Tabor’s theory can be applied to indentation hardness of cemented carbides, and it is shown that the alloys have the general features of plastic materials.
(2) In the Rockwell hardness, it is necessary to improve the shape of the indenter and to choose a suitable load in order to minimize the crack formation around the indentation and the effect of curvature indentation.
(3) Vickers hardness is dependent on the applied load. With decreasing applied load, the hardness values shifts up and the fractuation of values increases. Thus, it is required to set a suitable load.
(4) If suitable ball diamond cone is used, the stress-strain characteristics of cemented carbides can be obtained from Meyer’s exponential relation by ball indentations.
