| dc.description | This paper reports the friction and wear response of WC–10%Co(Cr/V) cemented carbide with different
surface finishes, attained by grinding (G) and wire-EDM, respectively, during sliding experiments at
400 °C. For comparison, tests under the same conditions were carried out at 25 °C. The wear experiments
were performed under a normal force of 14 N, which produced a Hertzian maximum pressure of 3.10 GPa,
and a sliding speed of 0.3 m/s against WC–6%Co(Cr/V) balls of 6 mm diameter. At 25 °C the average values
of the friction coefficients were 0.36 ± 0.04 and 0.39 ± 0.06 for the ground and wire-EDM surface finishes,
respectively. The mechanical behavior of both systems at 25 °C was assessed by carrying out analytical calculations
of the stress field created by a circular sliding contact under a spherical indenter, where the residual
stresses were considered. The theoretical results are in agreement with the experimental data, indicating that
the wire-EDM sample has a specific wear rate, which is approximately 3.1 times greater than that corresponding
to the G sample at 25 °C. At 400 °C, an increase in the friction coefficients takes place up to values
of 0.75 ± 0.1 and 0.71 ± 0.8, for the ground and wire-EDM surface finishes, respectively. The increase was
associated to an adhesive mechanism, which is more pronounced for the G sample. However, for the
wire-EDM sample this increase was more linked to a marked abrasive mechanism. The wear rates for both
samples at 400 °C are similar to those obtained at 25 °C, which indicates that apparently the test temperature
does not have an important effect on the wear rate. However, it is known that temperature influences
considerably the residual stress nature. Therefore, these results were explained by taking into account the
wear mechanisms between the tribopairs in view of the mechanical characteristics and the morphological
features obtained from SEM coupled with EDS analysis. | |
