Deformation and elastic properties of WC-Co system sintered carbides in micro- and macroindentation
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The work of deformation of WC-Co system alloys in micro- and macroindentation was determined and the character of its change in relation to the binder phase content was shown. The work of deformation with a constant depth of indentation of the indentor is a more sensitive characteristic relative to the structure of tungsten sintered carbides than with a constant load.
The share of elastic deformation and of the work of elastic deformation of tungsten carbide is very significant in relatively brittle alloys with a low cobalt content while, on the other hand, in high-cobalt alloys the total work of deformation in indentation of the indentor is basically determined by the work of plastic deformation of the binder phase.
Determination of the modulus of elasticity of WC-Co system alloys from the unloading branch of the indentor indentation curves showed the possibility of establishment of this characteristic by that method. The divergence from the values obtained by the ultrasonic method is related to relaxation processes at comparatively low loading rates.
The deviation of the change in the work of elastic deformation in indentation of the indentor and of the modulus of elasticity of the alloys from linearity is related to features of their structure and primarily to the high degree of proximity of the carbide phase in the low-cobalt sintered carbides.
The increase in hardness with low loads for tungsten carbide and the relatively brittle low-cobalt sintered carbides in relation to the force in indentation of the indentor is the same as for many brittle refractory compounds.
KeywordsCarbide Brittle Elastic Deformation Tungsten Carbide Carbide Phase
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