ESTIMATION OF STRENGTH AND PLASTICITY OF WC–Co HARD METALS MADE ON THE BASE OF ULTRA-COARSE-GRAINED WC WITH A COBALT COATING
Abstract
The objective of the research is to evaluate the level of strength and plasticity under the conditions of tensile, bending and compression testing of a WC–Co hard alloy made of ultra-coarse grained cobalt-coated WC carbide. And also investigate the dependence of the strength limits Rт, Rbт, Rcт and the limit value of plastic deformation ep on the parameters of the microstructure of composites of this class.
It was established that the strength limits Rт, Rbт and Rcт significantly depend on the size of the WC grain (in the range from 20 to 80 μm) and the thickness of the cobalt coating (from 1.11 μm to 7.6 μm), which corresponds to the volume content of Co from 0.04 to 0.16. An increase in the average size of carbide grains and the volume content of cobalt by 4 times leads to a decrease in Rcт by 43%, Rт and Rbт by 86%. Plasticity increases significantly with an increase dWC and in the case of compression and is absent in the case of stretching of the ultra-coarse-grained WC–Co matrix hard alloy
